What it does
Recipes give oven heat in Celsius, Fahrenheit or gas marks, and they are written for either a conventional oven or a fan (convection) oven. This converter takes one temperature and shows it in all three scales for both kinds of oven, with the nearest gas mark and its usual name, such as “moderate” or “hot”.
A fan blows hot air around, so food cooks faster at the same setting. The usual rule is to set a fan oven about 20 °C (25 °F) lower. Both numbers are editable, because some makers suggest less. When the recipe also needs new amounts, use the recipe scaler, and the cups to grams converter turns cups into grams.
How to use it
- Type the temperature from the recipe. For gas marks, type 1 to 9, or 1/4 and 1/2.
- Choose its scale: °C, °F or gas mark.
- Say whether the recipe was written for a conventional or a fan oven.
- Read the setting for your oven. The matching gas mark row is highlighted in the table.
What each setting does
- Temperature and In: the number from the recipe and its scale.
- Recipe is for: if the recipe is for a fan oven, the conventional setting is worked out by adding the fan difference back on.
- Fan oven is cooler by: how much lower a fan oven is set, in °C and in °F (20 and 25 by default). The table’s fan column follows it.
- Reset: back to 180 °C, conventional.
Answers are rounded to whole degrees. The gas mark is the one nearest in °C; outside about 110 to 240 °C there is no gas mark.
Worked example
A recipe says 180 °C. That is 356 °F, closest to gas mark 4 (a moderate oven). In a fan oven, set 160 °C. An American recipe at 425 °F is 218 °C, gas mark 7, a hot oven.
FAQs
Why does 180 °C show as 356 °F when recipes say 350 °F? Recipes round to the nearest 25 °F. 350 °F is 177 °C, close enough for almost all cooking.
Do I always lower the heat for a fan oven? Only when the recipe was written for a conventional oven. Many newer recipes give both.
My cakes still burn. Many ovens run hot. An oven thermometer shows the real temperature.
Where the numbers come from
- °F = °C × 9/5 + 32. Gas mark settings: the usual UK cooker scale as printed on gas ovens and in UK recipes; fibub's own working.
- Fan oven 20 °C / 25 °F lower: a common rule of thumb given by oven makers; check your oven's manual.
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
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Last updated 2026-11-10.