Disclaimer

General information only

Everything on ToolBoxGenie — the tools, the worked examples and the explanatory articles — is published for general information. It is not professional advice and should not be treated as a substitute for it.

Financial calculations

The loan, EMI, interest, GST, discount and tip calculators implement standard, documented formulas, and each page states the formula it uses. They cannot know the specific terms of your agreement. Tipping in particular is a social convention rather than a calculation: the percentages offered are common defaults, not a recommendation, and what is customary varies by country and by venue.

Real lending involves processing fees, insurance requirements, day-count conventions, floating rates and rounding rules that vary by lender and by country. Real tax involves classifications, exemptions and rates that change. Use these figures to understand the shape of a decision, then confirm the number with your lender, accountant or a qualified financial adviser before committing to anything.

The mortgage and car loan calculators estimate a monthly cost from figures you supply. They are not quotes, they exclude closing costs and dealer add-ons, and their treatment of mortgage insurance and of sales tax on a trade-in follows common conventions that do not apply everywhere. The debt payoff calculator is a simulation: it applies interest monthly, holds minimum payments fixed where most lenders reduce them as a balance falls, and models no fees, promotional rates or new spending. The savings calculator applies one unchanging rate of return, which no real savings account or investment provides, and deducts no tax.

The NPS calculator rests on two assumptions you supply, neither of which anyone can know in advance. The National Pension System is market-linked and declares no rate of return, so the corpus shown is a projection from a figure you chose rather than a value the scheme has promised. The annuity rate is worse: it is a quote an insurer will make on the day you retire, it varies by annuity variant, and it moves with interest rates decades ahead of anything that can be forecast. Scheme charges, tax treatment on the way in and the way out, and any future change to contribution limits or exit rules are not modelled. Treat the pension figure as the shape of a decision, not as an income to budget against.

The sales tax and VAT calculators apply a rate you enter. No rate table is built into this site, because rates change and vary by jurisdiction and by what is being sold — check the current rate, and whether the item is taxable at all, with your own tax authority. Net worth figures are only as accurate as the valuations you enter, and nothing you type into any of these tools is stored or transmitted.

Health calculations

The BMI calculator applies the World Health Organization’s adult classification. BMI is a population-level screening measure: it cannot distinguish muscle from fat, does not apply to children or adolescents, and is a poor guide for athletes, pregnant people and older adults.

The BMR, TDEE and calorie calculators use published regression equations — Mifflin-St Jeor, Harris-Benedict and Katch-McArdle. These were fitted to groups and predict a group average, so an individual can sit meaningfully above or below the figure for reasons the inputs cannot capture, including body composition, thyroid function, medication and genetics. The activity multiplier is a self-assessment, and it moves the result far more than the choice of equation does.

The ideal weight calculator reports the Devine, Robinson, Miller and Hamwi formulas. All four originate in clinical medicine, where a height-based reference weight is used for drug dosing and ventilator settings — none was designed to tell a person what they should weigh, none accounts for build or muscle mass, and they disagree with one another by several kilograms. They are shown together, with the healthy BMI range, precisely so that no single number is presented as an answer.

The body fat calculator offers two estimates. The US Navy method (Hodgdon and Beckett, 1984) works from circumference measurements; the BMI-based method uses the Deurenberg equation and inherits every limitation of BMI described above. Both predict a group average and typically land within three to four percentage points of a reference measurement, with larger errors at the lean and heavy extremes — which is why the result is presented as a band and why implausibly low figures are refused rather than displayed. The reference methods themselves disagree by a couple of points. It is an estimate from a tape measure, not a body composition measurement, and it says nothing about where fat is carried, which matters more to health than the total does.

Nothing on this site diagnoses, treats or prevents any condition, and nothing here is dietary advice or a recommended intake. Consult a qualified healthcare professional or registered dietitian about your health, and do not delay seeking advice because of something you read here.

The one-rep max calculator estimates a maximal lift from a submaximal set using six published formulas. They were fitted to different populations on different lifts, they disagree — which is why all six and their spread are shown rather than one number — and none was calibrated much past ten repetitions. An estimate that reads high is a bar that does not go back up, so treat the range as the answer, load conservatively, and use spotters or safety pins for anything near a maximum. It is arithmetic, not coaching, and it is no substitute for a max tested under supervision.

The heart rate zone calculator estimates a maximum heart rate from age using published regression equations — Tanaka, the older 220-minus-age, and Gulati — and divides it into five zones by percentage of maximum or by the Karvonen reserve method. The spread around every age-based estimate is roughly ±11 beats per minute, which is wider than a training zone, so a substantial share of people sit a whole zone away from the figure for their age. The two zone methods can differ by more than twenty beats at the same boundary, and neither is more correct than the other. None of this accounts for medication that alters heart rate, for a cardiac condition, or for anything else about an individual. It is not a fitness test, not a training plan and not medical advice; if you have a heart condition, take medication affecting heart rate, or are returning to exercise after illness or a long break, speak to a doctor about appropriate intensity first.

The sleep cycle calculator is clock arithmetic on an assumed cycle length. Ninety minutes is a population average that varies between people, varies from night to night in the same person, and changes across a single night, so the times it produces are candidates to try rather than a schedule that is correct. It measures nothing: it cannot see what stage of sleep you are in, cannot detect a sleep disorder, and cannot tell you whether the total is enough. Persistent tiredness after a full night, difficulty falling or staying asleep, or snoring with pauses in breathing are matters for a doctor, and no arrangement of cycle boundaries substitutes for treatment.

Building and material estimates

The paint, concrete, square footage and tile calculators produce ordering estimates from the measurements you enter. They are arithmetic on those figures and cannot see the job: a room out of square, a surface more porous than the product assumes, a pattern that must line up across a threshold, or a substrate that needs preparing will all move the real quantity. Each page states its method and the allowance it applied.

Treat the output as a starting point for a conversation with your merchant or trade, not as a specification. Wastage allowances are trade rules of thumb rather than standards, product coverage rates vary between brands and batches, and structural work in particular should be specified by someone qualified to do so. Check a supplier’s returns policy before opening every box or tin.

The wallpaper calculator counts drops rather than area, which is the trade method and is why it does not agree with an area calculation. It still cannot see the room: sloping ceilings, chimney breasts, dormers, stairwells and anything hung horizontally all change the count, usually upwards, and where the pattern is centred and which corner the papering starts from are decisions made with a plumb line rather than a calculator. Measure the walls yourself, and order the spare roll from the same batch — colour varies measurably between print runs.

The board foot calculator prices volume, not usable material. How much of a board survives to the finished piece depends on its defects and on how your parts are laid out, which is why the waste allowance is a figure you supply rather than one this site invents.

The fence calculator produces an ordering quantity from a run length: posts, rails, pickets and the concrete for the holes. The burial depth it uses is the trade rule of thumb — a third of the post in the ground, minimum 600 mm — and that is a guideline rather than a code requirement. Where the ground freezes the footing has to reach below the local frost line or the post will lift, and that depth comes from your building department. Fence height is regulated in most places, commonly above 2 m in the UK and 6 or 7 feet in much of the US, and at that height wind load governs the post and footing design rather than any rule of thumb.

The stair calculator produces an equal-riser flight from the rise you enter and checks it against the International Residential Code’s figures for riser height, tread going and headroom. Those figures are quoted as a reference. The code that governs a particular stair is the one adopted by its local authority and it may differ — the UK’s Approved Document K permits a steeper private stair, for one — so verify the limits in force where you are building. Stair geometry is a life-safety matter and is inspected as one; nothing on that page replaces your building control officer.

The metal weight and tank volume calculators describe ideal geometry. Real stock carries a rolling tolerance on every dimension and real tanks have wall thickness, weld seams, baffles, sumps and dished ends, so both figures are nominal. Where the number carries consequences — a lifting plan, a shipping declaration, a custody transfer or a fuel reconciliation — use the mill certificate, the weighbridge or the vessel’s own calibration chart, which are the authorities for exactly this reason.

The ramp slope calculator reports the gradient, run, landings and footprint implied by a rise, against the figures published in the Americans with Disabilities Act Standards or the UK’s Approved Document M, whichever you select. Those are two standards among many: the requirements that actually apply are set by the code adopted where the ramp is built, and codes differ on gradient, landing size, width and handrail geometry. Gradient and landings are also only part of a compliant ramp — surface finish and slip resistance, cross-slope, edge protection, handrail height and extension, the level approach at each end and the clear space at doors all matter, and none of them is a number this can check. Accessibility is a legal obligation in most jurisdictions and is inspected as one; nothing on that page replaces the code in force or the person who enforces it.

The lumens to lux calculator gives the light arriving directly from a source over an area, and nothing else. It does not model light reflected from walls, ceiling and floor, which in a small pale room adds meaningfully to what a meter reads and in a large dark one does not; it does not model more than one fitting, the fall-off across a room, glare, or how a lamp’s output declines over its life. The recommended levels shown for comparison are widely used conventions rather than a standard applicable to your building. A lighting design that has to satisfy a code or a specification is a job for the published standard and, past a certain point, a lighting engineer.

Electrical calculations

The Ohm’s law, LED resistor, voltage divider, resistor network, capacitor, RC, LC, battery and voltage drop calculators implement standard relationships and state the formula they use. They describe DC, or the RMS values of a purely resistive AC load. Anything with significant reactance — a motor, a transformer, a fluorescent ballast, a switch-mode supply — draws current out of step with the voltage, and applying a resistive model to one will overstate the power.

None of these tools tells you what is safe. In particular, the wire gauge converter and the voltage drop calculator give conductor geometry and the resistance that follows from it; they do not give an ampacity. How much current a cable may carry depends on its insulation rating, the ambient temperature, grouping with other cables and the installation method, and those figures live in the wiring regulations that apply where you are — NEC 310.16, IEC 60364-5-52 or your national equivalent. Resistance is physics; ampacity is a regulation, and a cable has to satisfy both it and the voltage drop limit.

The three-phase power calculator adds the AC case the paragraph above excludes: it relates kW, kVA, kVAr and line current through the power factor you supply. It assumes a balanced load, which a motor is and a building full of single-phase circuits is not, and its current figures are a design starting point rather than a conductor sizing — that still depends on the installation method, grouping, ambient temperature and the regulations named above. Power factor correction beyond a modest installation needs designing rather than calculating, because capacitors on a supply carrying harmonics can resonate with the network.

Electrical installation work is licensed in most jurisdictions for good reason. Mains voltages kill, and an undersized conductor is a fire risk that gives no warning. Use these pages to understand a circuit or to check your own arithmetic on low-voltage electronics; have anything connected to a mains supply designed, installed and inspected by a qualified electrician.

The solar panel and AC BTU calculators are sizing estimates and are labelled as such on their pages. The solar figures depend on the peak sun hours and loss percentage you enter and can express neither shading nor roof orientation, both of which move real output substantially; the page reports energy only and makes no claim about cost, payback or savings. The BTU figure is the published rule of thumb rather than a load calculation — ACCA Manual J models insulation, glazing, air leakage and humidity separately and commonly lands twenty to thirty per cent away in either direction. Have either system specified by an installer before buying equipment.

The 555 timer, op-amp gain and transformer calculators are bench arithmetic on idealised parts. The 555 formulas assume the timing capacitor is the value printed on it, which an electrolytic frequently is not; the op-amp results model an ideal amplifier with three real limits bolted on — output swing, gain-bandwidth and slew rate — and say nothing about offset, bias current, noise or stability into a capacitive load; and the transformer relations omit winding resistance, leakage inductance and core saturation, so the secondary voltage under load will sit below the figure shown. None of the three is a substitute for the datasheet.

Work on the primary side of anything connected to a mains supply is dangerous and is governed by the wiring rules where you are. These pages are for design and diagnosis; they are not instructions, they do not assess whether a circuit is safe to build or energise, and nothing on them replaces a qualified person.

Laboratory and solution calculations

The dilution calculator solves C₁V₁ = C₂V₂ on the numbers you enter. It has no idea what is being dissolved, what concentration is safe, or what the consequences of an error would be, and it applies no limit of any kind. It is workshop and laboratory arithmetic — buffers, stock solutions, cleaning concentrates, plant feed — and it is not a medical or pharmaceutical dosing tool. Dilution in a clinical setting is a controlled procedure for a pharmacist, not a web page. The same applies to anything you intend to drink, inhale or apply to skin.

The molarity calculator is the same kind of arithmetic one step earlier: it relates a mass, a volume and a concentration through a molar mass you supply. It does not know what is being dissolved, whether it will dissolve at all, or what concentration would be safe, and it applies no limit. Two things it cannot see are worth stating because they are systematic errors rather than random ones — a reagent’s purity, which is why that is an input, and whether the bottle holds a hydrate. Copper sulfate pentahydrate is 249.68 g/mol against 159.61 anhydrous, and using the wrong figure puts every solution from that bottle out by the same third.

The chemical equation balancer is a counting exercise and nothing more. It establishes how many atoms of each element sit on each side; it does not know whether the reaction happens at all, at what temperature, how fast, what catalyst it needs, which products actually form, or what any of it would do in a room. Plenty of perfectly balanced equations describe reactions that never occur, and some describe reactions nobody should attempt. Use it for stoichiometry and coursework, and take the safety of a procedure from a risk assessment and a supervisor rather than from a page that has only counted atoms.

The ideal gas law calculator solves PV = nRT on the numbers you give it. Two of those numbers have to be absolute: the temperature in kelvin, which the page converts for you, and the pressure measured from vacuum rather than from atmospheric. A gauge reading is not absolute pressure, and nothing can detect that mistake from the number alone. The ideal gas law itself is an approximation that degrades near condensation and at high pressure, and it is not a tool for specifying, filling or testing a pressure vessel — that is regulated work with its own standards and its own margins.

The half-life calculator is arithmetic on an exponential curve. It knows nothing about which isotope you have, what radiation it emits, how energetic that radiation is, or what dose any of it represents, and none of those follow from the half-life. It is not a radiological assessment and it is not a drug elimination calculator: clinical half-lives are population averages that vary with organ function, other medicines, age and genetics, and the interval between doses is a decision for a prescriber. The built-in isotope half-lives are nominal published figures for working through a problem, not values to cite.

The pH calculator applies the standard equilibrium arithmetic to the numbers you enter, with pKw interpolated from the published table so that neutral moves with temperature rather than sitting at 7 regardless. It uses concentration where the definition calls for activity, which holds below roughly 0.1 mol/L and drifts above it, and it models neither buffers nor the second and third protons of a polyprotic acid. It is coursework and bench arithmetic: a calibrated meter is the measurement, and this is the prediction. Nothing here is guidance on handling an acid or a base safely.

The specific heat calculator solves Q = mcΔT, which describes a substance staying in one phase and nothing else. A range crossing a melting or boiling point is not slightly wrong but answering a different question, and the tool says so when you give it a starting temperature — the latent heat involved is several times the heat of the temperature change either side of it. Specific heat is also temperature-dependent and, for gases, depends on whether pressure or volume is held constant; the table holds the usual room-temperature constant-pressure figures. It gives energy, not power, and is not a heat-loss calculation for sizing equipment.

The projectile motion calculator computes the vacuum trajectory: no air resistance, no wind, no spin, flat ground, constant gravity. That is the model introductory physics teaches and it is close for a dense, slow object over a short distance. It is badly wrong for anything light or fast — a struck golf ball travels roughly half the range shown, a bullet a small fraction of it — and because drag grows with the square of speed there is no correction factor that rescues it. It is not a ballistics tool, and nothing here should inform the use of anything that is fired.

Vehicle and mechanical estimates

The tire size calculator compares the nominal geometry two size codes describe. Real tyres vary between manufacturers at the same marking, and the loaded radius is smaller than the free radius because the tyre deflects. Nothing here addresses fitment: whether a size clears the arches, suspension and brakes through the full range of travel and steering lock, and whether its load index and speed rating suit the vehicle, comes from the manufacturer’s approved list. The gear ratio calculator assumes the efficiency you select and cannot see lubrication, alignment or wear.

The engine displacement calculator is geometry on the bore, stroke and cylinder count you enter — it describes the engine you describe to it. A published capacity may differ, because manufacturers round the badge and almost always upward, and because a rebored or restroked engine no longer matches its factory figures. Where capacity has a legal consequence — taxation, insurance, a racing class — the registration document and the governing body’s own measurement are what count, not a calculation from dimensions.

The horsepower calculator converts between torque, engine speed and power, which is an exact relation. Its wheel-to-crank estimate is not: the drivetrain percentages offered are the conventions the tuning world uses, and a real loss moves with the gear the run was done in, oil temperature, tyre pressure and how the dynamometer was operated. Two machines rarely agree on the same car, so the useful comparison is before and after on the same one.

The pulley belt calculator is centreline geometry for two pulleys in a plane. It says nothing about how much power a belt can transmit, what tension it needs, or how long it will last — those depend on the belt section and material, the service factor for the driven machine and the minimum pulley diameter the belt tolerates, all of which come from the manufacturer’s selection tables. A geometrically valid drive can still be the wrong drive.

Statistical calculations

The confidence interval, linear regression and binomial probability calculators compute standard textbook quantities correctly from the numbers you enter. What they cannot do is tell you whether those numbers meet the assumptions the arithmetic rests on. A confidence interval describes sampling error alone and says nothing about a sampling frame that missed part of the population, a leading question or a non-response pattern related to the answer — biases shift the estimate rather than widening the interval, and no sample size corrects them. A regression measures how two quantities move together and is equally consistent with either causing the other, with a third thing causing both, or with coincidence. The binomial distribution assumes a fixed number of independent trials at a constant rate, and real processes violate independence quietly and often.

Statistical significance is not importance, a p-value is not the probability that a hypothesis is true, and a confidence level is a property of the procedure rather than of the particular interval in front of you. Where a result carries real consequences — a clinical, regulatory, financial or legal decision — the study design and the choice of method matter more than the calculation, and both are work for someone qualified to do them.

Date and time calculations

Date tools use documented conventions — day counts exclude the end date unless stated, and business-day counts remove only Saturdays and Sundays. Public holidays vary by country, state and industry and are not deducted. Where a legal deadline matters, check the convention specified in the relevant contract or statute.

The ISO week number calculator implements ISO 8601: week 1 is the week containing the first Thursday of January, weeks run Monday to Sunday, and every calculation is performed in UTC so the answer does not change with the viewer’s time zone. Other week-numbering conventions are in common use — several start the week on Sunday, and several call the week containing 1 January week 1 regardless of how few days it holds — and they disagree with ISO for much of the year. Payroll periods, retail calendars such as 4-5-4, and fiscal weeks are separate systems again. Before comparing a week number against one produced elsewhere, establish which convention produced it.

Unit conversions

The converters use the exact internationally agreed definitions of each unit, and each page states the base unit it converts through. Two things still need your judgement: which unit family a source figure belongs to — a US pint and an imperial pint share a name and are not the same size — and how much rounding is acceptable for your purpose.

Where a unit is not a fixed quantity, the page says so. Mach depends on air temperature and is quoted here at sea level; the month and year used by the time converter are calendar averages rather than the length of any particular month. For a gap between two real dates, use the date difference calculator instead.

Three converters need a stronger caveat. The radiation converter separates equivalent dose, absorbed dose, activity, dose rate and exposure, and will not convert between them — becquerels cannot become sieverts without the isotope, geometry and exposure time, and no unit converter has those. It reports units only and states no exposure limit or safety threshold; those are matters for a qualified radiation protection adviser and the applicable standards. The PPM converter’s mg/L entries assume a solution that is essentially water; for any other solvent the equivalence with parts per million does not hold. The molar mass tool uses standard atomic weights, which are averages over naturally occurring isotopes and do not describe enriched or depleted material.

Gas marks are not a temperature scale but numbered valve positions, so the cooking temperature converter reports the nearest mark against conventional published equivalents rather than an exact conversion, and the fan oven adjustment is the usual rule of thumb rather than a specification for your appliance.

The viscosity converter separates dynamic from kinematic viscosity and will not convert between them, for the same reason the radiation converter keeps its quantities apart: the bridge is the density of your particular fluid at your particular temperature. Viscosity is also strongly temperature dependent, so a figure quoted without a temperature is incomplete whatever unit it is in.

The shoe size converter computes from the published definitions of each scale, not from any manufacturer’s chart, and it is a guide to which size to try rather than a statement about fit. Length is one dimension of three, lasts differ in width and volume between and within brands, and the allowance between foot and last is a design choice — which is why that allowance is an input on the page and why changing it can move the answer by a full size.

The ring size converter works the same way and carries the same limit. Every scale it converts between encodes one measurement — the inner circumference — so the conversions are exact, and none of that tells you what will fit. Fingers change size through the day and the year, the knuckle is usually wider than the base of the finger, and a wide band fits tighter than a thin one at the same nominal size. For a ring that matters, a jeweller’s sizing set tests the fit rather than inferring it.

The GPS coordinate converter reformats a position and does not reproject it. All three notations it produces assume the WGS-84 datum, which is what satellite navigation and modern mapping use. A coordinate taken from an older survey on a national datum can sit hundreds of metres from its WGS-84 position, and no change of notation corrects that.

Shipping and commercial terms

The dimensional weight calculator applies the volumetric formula carriers use and the divisor you select. Divisors are commercial terms rather than standards: they differ between carriers, between domestic and international services, and between contract and retail rates, and carriers change them. The figure produced here is a chargeable weight, not a quote — fuel, remote-area, residential, oversize and handling surcharges sit on top, minimum billable weights can override the result, and the carrier measures the parcel as it arrives at the depot rather than as you described it. The divisor and the terms on your own rate card are the ones that govern your invoice.

Developer and text tools

Formatters, validators, encoders and the regex tester use the browser’s own engines and follow the relevant specifications. They are debugging and authoring aids, not security controls. In particular, decoding a token shows you what it claims; it does not verify that the claim is true.

The string escaper deserves saying twice, because its SQL option is the one most likely to be misread. Doubling a single quote is what a standard SQL literal does and is useful for writing a query by hand; it is not injection protection, it does not know your server’s escape settings, and it cannot see the context the value lands in. Parameterised queries are the defence in application code, and nothing this page produces substitutes for them.

The security-adjacent tools carry the same caveat. The hash generator computes digests with your browser’s Web Crypto implementation, and a matching checksum proves only that the bytes are the ones that were hashed — not that the source you took the checksum from can be trusted. The password generator uses the platform’s cryptographic random number generator and reports the entropy of its own output; how safe a password is in practice depends on where you store it and whether it is reused, neither of which any generator can influence.

Two of those tools carry limits worth stating on their own. The text encrypter uses the browser’s AES-256-GCM and PBKDF2; the encryption is only ever as strong as the passphrase chosen for it, there is no way to recover a message whose passphrase is lost, and the page offers no identity, signature or forward secrecy. The SVG optimiser removes script elements and inline event handlers and reports what it found, but it is a cleaner rather than a sanitiser and should not be relied on to make a file from an untrusted source safe to inline.

The SVG to PNG converter draws the file through an image element, where the browser runs no script and fetches nothing from outside the file. That is what makes it safe to convert an SVG you did not write, and it is also why a webfont or a picture the file loads from a URL will be missing from the PNG rather than drawn into it. The tool warns when it finds such a reference, but the warning is a scan of the markup and not a guarantee that it found every one.

The typing speed test measures one attempt at one passage in one sitting, which is a noisy sample of how fast anyone types. The speed bands beside the result are the figures commonly quoted for adult typists, not a scale anybody administers, and nothing here is a certified typing assessment: an employer who requires a WPM figure will have their own test. No score is stored, so there is no record of a result to produce later.

The password strength checker analyses what you type in your browser and transmits, stores and logs nothing — but it asks you not to type a password you actually use, and that request is the important part of the page. You cannot verify that claim on any website by reading it, this one included, so the habit is worth avoiding whatever the site says. Both figures it reports are estimates rather than measurements: it has no dictionary, so a common word, a name, or a password from a past breach shows no structure here and would still be guessed in seconds. A result of “no patterns found” is not a statement that a password is safe to use.

The CSP generator builds a header from what you type and lints that text. It never fetches your site, so it cannot know what your pages actually load, and a policy that raises no warnings here can still break something or leave a gap. It is not a security audit, and a Content-Security-Policy is one control among many rather than a substitute for fixing what lets untrusted markup into a page. Deploy in report-only mode and read the reports before enforcing.

The JSONPath tester implements the portable subset of a syntax that only became a specification — RFC 9535 — in 2024, so an expression that works here may still behave differently in a library that predates it or extends it. Script expressions and functions are refused rather than approximated, which means a query this page rejects is not necessarily invalid elsewhere. Check any expression against the implementation that will actually run it.

The redirect map generator produces configuration for you to review, not to deploy unread. It checks the map as a graph — loops, chains, duplicate sources, mixed trailing slashes — but it cannot see your server, so it does not know what other rules already exist, in what order they match, or whether a path collides with a real route. Test on a staging environment before a live site, and remember that a 301 is cached hard by browsers and correspondingly hard to take back.

The image redaction tool overwrites the pixels under each area you mark before the file is written, so the exported PNG does not carry the original values, and the page reports how many distinct colours survive in each area. Three limits are worth stating plainly. A solid fill is the only mode with nothing left to invert — pixelation of predictable content such as digits has been reversed by published research, and blur is a linear operation that can be partially undone. It only covers what you mark, so anything visible elsewhere in the same picture is still there. And it acts on the copy it exports: the original file on your device is untouched, metadata included.

The barcode generator produces valid EAN-13, EAN-8 and UPC-A symbols and calculates their check digits, which is a different thing from allocating a number. Retail product numbers are issued by GS1, and a number you choose yourself may already belong to another company’s product. For any use that crosses a shop counter, obtain a company prefix from your national GS1 organisation; for internal purposes, any number works. Verify a printed symbol with a real scanner before committing to a print run — a barcode that reads on a phone camera can still fail at a till.

The sunrise and sunset calculator implements NOAA’s solar position algorithm, which NOAA states as accurate to about a minute between 72° north and south and less so beyond that. It assumes sea level and a flat horizon, so local terrain moves the real times by more than any refinement in the algorithm would: a hill to the east delays sunrise, and altitude brings it forward. It is not a sole source for anything where the timing carries a legal or safety consequence — aviation, marine navigation and religious observance all have their own authoritative tables.

The moon phase calculator computes the geocentric phase: the fraction of the disc lit, which is the same for every observer on Earth at a given moment. Two things it deliberately does not do. It does not give moonrise or moonset, which depend on your location and are a separate calculation. And it does not predict crescent visibility, which is not the same question as the phase — whether a new crescent can actually be seen depends on its altitude, its separation from the Sun, the air and the observer, and it is the basis of religious calendar determinations that are made by observation and by the authorities responsible for them, not from a phase figure on a web page.

The image to PDF tool writes a document containing images and nothing else, in your browser. Images are re-encoded as JPEG on the way in, so a PNG becomes lossy at that step and any transparency is flattened onto white; the page says so where you will read it. The PDF writer is deliberately minimal — no text, no fonts, no encryption and no reading of an existing PDF — and what it produces is not a certified or archival-format document.

The recipe scaler multiplies quantities and nothing else. Cooking times, pan and tin sizes, and the amounts of salt, spice, yeast and chemical leavening do not scale in proportion, and the page says so alongside the result. Where a recipe involves food safety — a cure, a preserve, a fermentation, a canning process — the ratios and timings are the safety control, and those recipes should be followed as published rather than rescaled. The baker’s percentage calculator converts between weights and percentages of flour weight and makes no judgement about whether a formula will work: hydration, salt and leavening figures outside the usual ranges are flagged as unusual, not as wrong. The baking pan converter compares two pans by volume and reports the factor between them; its notes on oven time and temperature are rules of thumb that follow the change in batter depth, and they cannot account for the batter, the pan’s material and colour, or how accurately an oven holds its setting.

The HMAC generator and the curl converter both handle secrets, and both do so entirely inside your browser — no key, message, command or generated code leaves the page. What neither can do is control what happens next. A signature that matches proves the message was produced by a holder of the key; it does not establish that the message is safe to act on, and comparing signatures in a browser tab is not the same as verifying them on a server, where the comparison has to resist timing measurement and the key has to be stored somewhere other than in the source. The converter’s output is a faithful translation of a curl command, error handling included only in outline, and any credential in the command comes across as a literal string that belongs in an environment variable before the file is saved.

The colour blindness simulator uses the Brettel-Viénot-Mollon model, which represents the three dichromacies — a missing cone type — and does not represent anomalous trichromacy, the far more common milder form. It is a design aid for checking whether a distinction survives, not a claim about how any individual experiences colour, and passing it says nothing about text contrast, keyboard operation, labelling or any other accessibility requirement. The MAC address formatter reformats and inspects an address you supply and performs no lookup of any kind; the vendor registry it names is published by the IEEE, and this site holds no copy of it and no device data.

Photographic estimates

The depth of field calculator rests on a threshold called the circle of confusion, which is a judgement about viewing rather than a property of a lens. The convention used — the sensor diagonal divided by 1500 — assumes a print viewed at its own diagonal with normal eyesight, and it is the same assumption behind the distance scales engraved on manual lenses. Inspect a high-resolution file at full magnification instead and the range that reads as sharp is a fraction of the figure shown, which is why the threshold is an editable field on the page.

The formulas are the thin-lens results and ignore pupil magnification and bellows extension, both of which shift real depth of field slightly at close range. Depth of field also has no hard edge: blur grows continuously either side of the focus plane, and the near and far limits are simply where it crosses the chosen threshold.

Academic calculations

The attendance, CGPA and final grade calculators do arithmetic on figures you supply. What that arithmetic means is set by an institution, and institutions differ: whether medical or approved absence is excluded from an attendance count, whether the requirement applies per subject or in aggregate, how a figure is rounded at the boundary, whether a shortfall can be condoned, and which grade points and weightings a programme uses are all rules in a handbook rather than properties of the numbers.

None of these pages can tell you whether you will be permitted to sit an examination or what grade you will be awarded. Where a result is anywhere near a threshold, the published regulations govern and the department is the place to check.

Accuracy and availability

We take accuracy seriously and correct reported errors quickly, but we do not warrant that every result is free from error, nor that the site will always be available. If you find a wrong result, please report it through the contact page with the values you entered — it will be investigated.

External links and advertising

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Limitation of liability

To the fullest extent permitted by law, ToolBoxGenie accepts no liability for any loss or damage arising from use of, or reliance on, any tool or content on this site. Your use of the site is at your own risk. See the terms of service for the full provisions.

Contact

Questions about this disclaimer can be sent to sidhin.p.s2020@gmail.com.