Four ways to describe the same heat
Recipes from different countries describe oven heat in different ways:
- Fahrenheit (°F) in the United States.
- Celsius (°C) in most of the world, including Canada and Australia.
- Gas mark in older British and Irish recipes, from ¼ to 10.
- Thermostat (Th) in French recipes, on a scale where each step is 30 °C.
The formulas
- °C = (°F − 32) ÷ 1.8, and °F = °C × 1.8 + 32
- Gas mark 1 = 275 °F, and each mark adds 25 °F up to gas mark 9 (475 °F). Gas mark ½ is 250 °F and gas mark ¼ is 225 °F.
- Th = °C ÷ 30, so Th 6 is 180 °C and Th 7 is 210 °C.
Common settings
| Description | °F | °C | Gas mark |
|---|---|---|---|
| Very low | 250 | 120 | ½ |
| Low | 300 | 150 | 2 |
| Moderate | 350 | 175 to 180 | 4 |
| Moderately hot | 375 | 190 | 5 |
| Hot | 400 to 425 | 200 to 220 | 6 to 7 |
| Very hot | 450 to 475 | 230 to 245 | 8 to 9 |
Convection (fan) ovens
A fan blows hot air around the food, which cooks it faster and more evenly. Most recipes written for a conventional oven work in a convection oven at about 25 °F (about 15 to 20 °C) lower, or at the same temperature with a shorter time. Start checking 5 to 10 minutes before the recipe says. Some ovens apply this adjustment automatically in convection mode, so check your oven’s manual.
Example
A cake recipe calls for 350 °F in a conventional oven, and your oven has a fan:
- 350 °F = 177 °C, gas mark 4, thermostat 5.9
- Set your convection oven to 325 °F
Tips
- Many ovens run hotter or cooler than the dial says. An oven thermometer placed in the center shows the real temperature.
- Preheat for at least 15 minutes, longer for bread or pizza.
- Dark metal pans brown faster than glass or light pans; lower the heat by about 25 °F for glass dishes.
- Air fryers are small convection ovens: use the air fryer calculator for those.