Oven Temperature Converter
Celsius, fan oven, Fahrenheit and gas mark, converted the way cookbooks round them.
The standard oven temperature chart
110 °C = 225 °F = gas ¼. 120 °C = 250 °F = gas ½. 140 °C = 275 °F = gas 1. 150 °C = 300 °F = gas 2. 160 °C = 325 °F = gas 3. 180 °C = 350 °F = gas 4. 190 °C = 375 °F = gas 5. 200 °C = 400 °F = gas 6. 220 °C = 425 °F = gas 7. 230 °C = 450 °F = gas 8. 240 °C = 475 °F = gas 9. These pairs are rounded conventions that every cookbook shares; the exact math differs by a few degrees, which no oven can hold anyway.
Fan (convection) ovens
A fan circulates the hot air, so food cooks as if the oven were about 20 °C (roughly 35 °F) hotter. When a recipe gives a conventional temperature and your oven is fan-only, set it 20 °C lower. Many modern recipes list both: 200 °C (180 °C fan) means the same oven heat.
Gas marks
Gas marks are the scale on British and Irish gas ovens. Gas mark 1 is 275 °F and each mark adds 25 °F; marks ¼ and ½ cover very slow ovens below that. Old recipes saying 'a moderate oven' mean roughly gas 4, 180 °C.