Oven temperatures: Celsius, Fahrenheit, gas mark and fan
Quick answer: Take 20 °C off a conventional temperature for a fan oven. 180 °C conventional is 160 °C fan, 350 °F, gas mark 4. 200 °C is 180 °C fan, 400 °F, gas mark 6. The full chart is below.
Recipes travel further than ovens do. An American recipe gives Fahrenheit, a British one might give gas marks or a fan setting, and a European one assumes whatever oven the writer happened to have. The numbers are easy to convert once you know the three systems and the one adjustment that catches most people out: the fan.
The conversion chart
These are the settings recipe writers use, rounded the way oven dials are marked. They are not exact arithmetic conversions, because nobody sets an oven to 177 °C.
| Conventional °C | Fan °C | °F | Gas mark |
|---|---|---|---|
| 110 °C | 90 °C | 225 °F | ¼ |
| 120 °C | 100 °C | 250 °F | ½ |
| 140 °C | 120 °C | 275 °F | 1 |
| 150 °C | 130 °C | 300 °F | 2 |
| 160 °C | 140 °C | 325 °F | 3 |
| 180 °C | 160 °C | 350 °F | 4 |
| 190 °C | 170 °C | 375 °F | 5 |
| 200 °C | 180 °C | 400 °F | 6 |
| 220 °C | 200 °C | 425 °F | 7 |
| 230 °C | 210 °C | 450 °F | 8 |
| 240 °C | 220 °C | 475 °F | 9 |
Why fan ovens need a lower setting
A fan oven blows hot air around the food. Moving air carries heat into the food faster than still air at the same temperature, which is why the usual advice is to turn the dial down by about 20 °C. Most British ovens are fan assisted, and most British recipes written in the last twenty years give both figures. American recipes almost always assume a conventional oven without a fan, so a British cook following one should take 20 °C off.
Some ovens adjust for this themselves. If your oven manual says the fan setting is already compensated, use the conventional figure. If the first batch browns early, your oven runs hot, which is common. An oven thermometer costs very little and settles the question for good.
Gas marks
Gas marks are a British and Irish scale from the days of gas cookers. They run from ¼ to 9. Each step above gas mark 1 is roughly 15 °C, which is why gas mark 4 sits at 180 °C and gas mark 6 at 200 °C. A gas oven is hotter at the top than the bottom, so the stated mark refers to the middle shelf.
Converting a temperature that is not in the chart
To go from Fahrenheit to Celsius, subtract 32 and multiply by five ninths. To go from Celsius to Fahrenheit, multiply by nine fifths and add 32. Then round to the nearest 10 °C or 25 °F, because that is how ovens are marked.
Air fryers
An air fryer is a small, very fast fan oven. A common starting point for converting an oven recipe is to lower the temperature by about 20 °C and cut the time by about a fifth, then check early. Food sitting close to the element browns quickly, so give it a shake halfway through and judge by colour rather than the clock.
Read next
- Cups to grams: why a cup of flour is not a cup of flour
A cup measures volume, not weight, so every ingredient weighs something different. Here is what that means for baking.
- Cooking an American recipe in a British kitchen
Cups, sticks of butter, Fahrenheit, gas marks, tin sizes and the ingredient names that mean something else here.
- Baking tin sizes: how to swap tins without ruining a recipe
Inch-to-centimetre tin sizes, how to scale a recipe to a bigger or smaller tin, and swapping round tins for square ones.
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