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ToolBoxGenie

Cooking Temperature Converter

Converters · Added 15 August 2026

Convert oven temperatures between Celsius, Fahrenheit and gas mark, with the fan oven adjustment included. Celsius and Fahrenheit convert exactly; gas marks do not, because they are numbered positions on a valve rather than points on a temperature scale, so the tool reports the nearest mark rather than inventing a fractional one.

I have a temperature in
°C

Result

Conventional oven

180 °C · 356 °F

Gas mark 4 — moderate

Celsius
180 °C
Fahrenheit
356 °F
Gas mark
4
Fan / convection oven (−20 °C)
160 °C · 320 °F
Oven description
Moderate
Full gas mark chart
Gas mark°C°FFan °CDescription
¼11022590Very cool
½120250100Very cool
1140275120Cool
2150300130Cool
3170325150Warm
4180350160Moderate
5190375170Moderately hot
6200400180Fairly hot
7220425200Hot
8230450210Very hot
9240475220Very hot

Celsius and Fahrenheit convert exactly. Gas marks do not — they are valve positions, and the °C figures are the conventional published equivalents, which is why the chart rounds to tidy numbers. The fan adjustment is the usual −20 °C rule of thumb; check your oven's manual, as some manufacturers specify a different offset.

How to use the cooking temperature converter

  1. 1Choose whether you have a temperature in Celsius, Fahrenheit or a gas mark.
  2. 2Enter the value, or tap a gas mark.
  3. 3Read the equivalent in every other scale, including the fan oven setting.
  4. 4Open the full chart if you want to see the whole gas mark scale at once.
  5. 5Reduce by about 20 °C when using a fan oven with a conventional recipe.

Examples

A standard baking temperature

Input
180 °C
Result
356 °F · gas mark 4 · fan 160 °C

The most common oven setting in British and European recipes.

An American recipe

Input
350 °F
Result
177 °C · nearest gas mark 4 · fan 157 °C

350 °F is the American equivalent of the 180 °C default, near enough for baking.

A hot oven for bread

Input
Gas mark 7
Result
220 °C · 425 °F · fan 200 °C

Gas marks step in units of roughly 14 °C at the top of the scale.

About the cooking temperature converter

Why gas marks exist at all

Early gas ovens had no thermostat and no temperature reading — you set a valve and learned by experience. The gas mark scale, introduced in Britain in the 1920s, gave those valve positions numbers so that recipes could be written down and followed. It was a usability improvement over 'a moderate oven', which is what recipes said before.

Because the scale describes valve positions rather than temperatures, its relationship to degrees was established afterwards by measurement. The published equivalents are conventional round figures, which is why the chart shows tidy numbers like 140, 150 and 170 °C rather than the awkward decimals an exact conversion would produce.

The scale is also not linear at the bottom. It starts at mark ¼ and ½ before reaching 1, because low-temperature settings for slow cooking and meringues needed finer division than whole numbers allowed. Above mark 1 the steps are roughly even.

What actually matters when following a recipe from elsewhere

The temperature conversion is the easy part. The harder differences between recipe traditions are elsewhere: whether the oven is fan-assisted, where the shelf sits, and whether the recipe assumes a preheated stone or tray. A fan oven at the same number is meaningfully hotter in effect, which is the single most common reason a converted recipe overcooks.

Position matters more than people expect in a conventional oven. Without a fan, the top of the oven is hotter than the bottom, sometimes by twenty or thirty degrees, and recipes written for conventional ovens often assume a particular shelf. Fan ovens are far more even, which is their main advantage and also why they need the temperature reduction.

The reliable habit is to treat the number as a starting point and judge by the food. Colour, aroma, an internal temperature probe for anything substantial, and a skewer for cakes all tell you more than the dial does — particularly given how far a domestic oven's actual temperature can sit from its setting.

Frequently asked questions

Why do I reduce the temperature for a fan oven?
Because a fan circulates the air, which transfers heat to the food far more efficiently than still air at the same temperature. The usual guidance is to reduce the setting by about 20 °C, or roughly 25 °F, compared with a conventional recipe — some manufacturers suggest reducing the time instead, or both. Ovens vary, so treat it as a starting point and check the food rather than the clock.
Is 180 °C exactly gas mark 4?
By convention yes, but the conversion is not arithmetic. Gas marks are numbered settings on a gas valve, and the temperature each produces was established by measurement and convention rather than by a formula. The published chart gives gas mark 4 as 180 °C and 350 °F, even though 180 °C is actually 356 °F. The scale's steps are approximately 25 °F apart at the lower end and 14 °C at the top, which is why the chart's numbers are round rather than exact.
How do I convert Celsius and Fahrenheit by hand?
Multiply Celsius by 9/5 and add 32 to get Fahrenheit; subtract 32 and multiply by 5/9 to go the other way. For oven work a decent shortcut is to double the Celsius figure and add 30 — that gives 390 for 180 °C against a true 356, which is too rough for baking but fine for judging whether a recipe means a moderate or a hot oven.
Does oven temperature really matter that much?
It depends on what you are cooking. Roasting vegetables or meat tolerates a fair range. Baking does not: the temperature governs how fast the structure sets relative to how far the item spreads or rises, so cakes and pastry are genuinely sensitive to twenty degrees either way. Worth knowing too that most domestic ovens are inaccurate by 10–20 °C and swing considerably as the thermostat cycles — an oven thermometer is a cheap way to find out what yours actually does.

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