Oven temperature conversion chart
| Gas mark | Conventional °C | Fan oven °C | °F | Oven |
|---|---|---|---|---|
| 1 | 140 | 120 | 275 | Cool |
| 2 | 150 | 130 | 300 | Cool |
| 3 | 160 | 140 | 325 | Moderate |
| 4 | 180 | 160 | 350 | Moderate |
| 5 | 190 | 170 | 375 | Moderately hot |
| 6 | 200 | 180 | 400 | Moderately hot |
| 7 | 220 | 200 | 425 | Hot |
| 8 | 230 | 210 | 450 | Hot |
| 9 | 240 | 220 | 475 | Very hot |
Gas marks and Fahrenheit values are the rounded equivalents used in recipes, not exact conversions.
Fan oven or conventional?
A fan (convection) oven circulates hot air, so food cooks faster at the same setting. The usual rule is to set a fan oven about 20 °C lower than a conventional recipe temperature: 180 °C conventional becomes 160 °C fan.
Many recipes now give both temperatures, or write "180 °C (160 °C fan)". If a recipe only says "fan", don’t lower it again. In Fahrenheit, US recipes and oven manuals commonly suggest about 25 °F lower for convection baking.
How to convert Celsius and Fahrenheit
- Celsius to Fahrenheit: multiply by 9, divide by 5, add 32. 180 °C × 9 ÷ 5 + 32 = 356 °F, which recipes round to 350 °F.
- Fahrenheit to Celsius: subtract 32, multiply by 5, divide by 9. (400 °F − 32) × 5 ÷ 9 = 204 °C, which recipes round to 200 °C.
- Quick mental check: double the Celsius figure and add 30. It’s rough, but 180 °C → about 390 °F tells you you’re in the right range.
Common recipe temperatures
| Recipe says | Use (conventional) | Use (fan) | Typical use |
|---|---|---|---|
| 325 °F | 160–170 °C | 140–150 °C | Slow-baked cakes, cheesecake |
| 350 °F | 180 °C | 160 °C | Most cakes, cookies, brownies |
| 375 °F | 190 °C | 170 °C | Muffins, pies, casseroles |
| 400 °F | 200 °C | 180 °C | Roast vegetables, bread rolls |
| 425 °F | 220 °C | 200 °C | Roast potatoes, pizza, puff pastry |
Every oven runs slightly hot or cold. An inexpensive oven thermometer shows what yours really reaches, and checking food a few minutes early is the safest habit.