Oven temperature conversion
Gas marks, conventional and fan Celsius, and Fahrenheit side by side, for recipes written for someone else's oven.
| Gas mark | °C | °C fan | °F | Description |
|---|---|---|---|---|
| 110 | 90 | 225 | Very cool | |
| 120 | 100 | 250 | Very cool | |
| 140 | 120 | 275 | Cool | |
| 150 | 130 | 300 | Cool | |
| 170 | 150 | 325 | Warm | |
| 180 | 160 | 350 | Moderate | |
| 190 | 170 | 375 | Moderately hot | |
| 200 | 180 | 400 | Hot | |
| 220 | 200 | 425 | Hot | |
| 230 | 210 | 450 | Very hot | |
| 240 | 220 | 475 | Very hot |
Celsius figures are the rounded values printed in UK recipes (as used by BBC Good Food and Delia Online). The exact Celsius for each °F differs by a few degrees; for gas mark 4 it is 176.7 °C. Fan values follow the common "20 °C lower" rule; check your oven's manual.
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Why fan ovens run lower
A fan moves hot air across the food, which strips away the thin layer of cooler air that clings to its surface. Heat transfers faster, so the same result arrives at a lower set temperature. That is why most UK recipes print two numbers, such as "180 °C (160 °C fan)". American recipes usually assume a conventional oven; if yours is convection, the same 20 °C (about 25 °F) reduction is the usual starting point.
Where gas marks come from
Gas marks are a UK scale printed on gas cooker dials. From mark 1 upward each step is 25 °F: mark 1 is 275 °F, mark 4 is 350 °F and mark 9 is 475 °F, with ¼ and ½ below mark 1 at 225 °F and 250 °F.
Questions
What is gas mark 4 in Celsius?
Gas mark 4 is 180 °C in a conventional oven (160 °C fan) and 350 °F.
How much lower should a fan oven be?
Most UK recipe publishers and oven makers advise setting a fan (convection) oven about 20 °C lower than the conventional temperature, e.g. 160 °C fan instead of 180 °C.
What is 350 °F in Celsius for baking?
350 °F is 176.7 °C exactly; recipes round it to 180 °C (160 °C fan), gas mark 4.
What is 200 °C in Fahrenheit?
200 °C is 392 °F exactly; recipes usually say 400 °F, gas mark 6.