FlourScaleHow to convert oven temperatures
The formulas are simple: °C = (°F − 32) × 5 ÷ 9 and °F = °C × 9 ÷ 5 + 32. In practice, recipes round to the nearest convenient number, so 350°F (176.7°C) is written as 180°C, and 180°C (356°F) is written as 350°F. That small difference does not matter for baking because home ovens commonly swing by 10–25°F around the set point anyway.
Gas marks are a UK scale used on gas cookers. Each step is roughly 25°F (about 14°C) from gas mark 1 at 275°F upwards; marks ¼ and ½ cover very low temperatures for meringues and drying.
Oven temperature chart
| Gas mark | °F | °C | Fan °C | Description |
|---|---|---|---|---|
| ¼ | 225 | 110 | 90 | Very cool |
| ½ | 250 | 120 | 100 | Very cool |
| 1 | 275 | 140 | 120 | Cool |
| 2 | 300 | 150 | 130 | Cool |
| 3 | 325 | 170 | 150 | Moderate |
| 4 | 350 | 180 | 160 | Moderate |
| 5 | 375 | 190 | 170 | Moderately hot |
| 6 | 400 | 200 | 180 | Hot |
| 7 | 425 | 220 | 200 | Hot |
| 8 | 450 | 230 | 210 | Very hot |
| 9 | 475 | 240 | 220 | Very hot |
Fan, convection and air fryer adjustments
A fan (convection) oven circulates hot air, which transfers heat faster. The usual guidance is to reduce the temperature by about 20°C or 25°F from a conventional recipe, or keep the temperature and shorten the baking time. Many modern ovens apply this reduction automatically in convection mode, so check your manual before subtracting twice.
Air fryers are small, powerful convection ovens. A common starting point is to lower the temperature by about 25°F (15°C) and reduce the time by roughly 20%, checking early. Results vary a lot by model and basket size, so treat the air fryer figure as a first attempt, not a rule.
Worked example
A US recipe says "bake at 375°F". (375 − 32) × 5 ÷ 9 = 190.6, so set a conventional oven to 190°C, a fan oven to about 170°C, or a gas oven to mark 5.
Check your oven's real temperature
An inexpensive oven thermometer is one of the best baking investments. Place it in the centre, preheat for at least 15–20 minutes, and compare with the dial. If your oven runs hot or cold, adjust the setting rather than the recipe. Dark metal and glass pans also bake faster than light aluminium; lowering the temperature by about 25°F (15°C) helps prevent over-browned edges.