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ToolBoxGenie

Age Calculator

Calculators ยท Added 2 July 2026

Enter a date of birth and this calculator returns the exact age in years, months and days as of today โ€” or as of any other date you choose. It also breaks the same span down into total months, weeks, days and hours, and counts down to the next birthday.

Defaults to today โ€” change it to work out an age on any other date.

How to use the age calculator

  1. 1Pick the date of birth in the first field.
  2. 2Leave the second field on today's date, or change it to work out an age as of a past or future date.
  3. 3The result updates as soon as both dates are valid โ€” there is nothing to submit.
  4. 4Use Copy to put the full breakdown on your clipboard, or Reset to start again.

Examples

Age on a specific date

Input
Born 14 March 1998, calculated as of 8 August 2026
Result
28 years, 4 months, 25 days

That is 10,374 days, or roughly 1,482 weeks.

A child's age for a school form

Input
Born 2 September 2019, calculated as of 1 April 2026
Result
6 years, 6 months, 30 days

About the age calculator

Why exact age matters more than you'd expect

Most of the time, saying 'I'm twenty-eight' is enough. But a surprising number of processes need the exact figure: school admission cut-offs, insurance premium bands, pension eligibility, visa applications, sporting age groups and clinical dosage guidelines all key off a precise date rather than a rounded year.

Those systems rarely agree on how to round, either. An age-group cut-off might be measured as of 1 September, while an insurance band is measured on the policy start date. Being able to compute an age as of an arbitrary date โ€” not just today โ€” is what makes the difference between guessing and knowing.

Years, months and days versus total days

There are two honest ways to express the gap between two dates, and they answer different questions. The calendar breakdown (28 years, 4 months, 25 days) is what a form wants. The total-days figure (10,375 days) is what you want for anything cumulative โ€” tracking a milestone, calculating accrued interest, or working out how many days of leave someone has built up.

Because calendar months vary between 28 and 31 days, you cannot convert cleanly between the two. This is why the tool shows both rather than making you pick.

Frequently asked questions

How is age calculated exactly?
The calculator subtracts calendar components rather than dividing a total number of days. It first takes the difference in years, then months, then days, borrowing from the previous month when the day-of-month is smaller in the end date. This is the same method used on official forms, and it is why an age can be '1 year, 0 months, 30 days' rather than a fractional year.
Does it handle leap years?
Yes. All arithmetic is done on real calendar dates, so 29 February is counted when it exists and skipped when it does not. Someone born on 29 February is treated as having their birthday on 1 March in non-leap years for the countdown.
Why does my age in months not equal years times twelve?
Months have different lengths, so a 'total months' figure counts complete calendar months elapsed. A person aged 2 years and 11 months has lived 35 complete months, not 24.
Is my date of birth stored anywhere?
No. The calculation happens in your browser with JavaScript. Nothing is transmitted to a server and nothing is saved after you close the tab.

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