Oven Temperature Conversions: Fahrenheit, Celsius, and Gas Marks Without the Guesswork

Recipes from different countries measure oven heat differently: US recipes use Fahrenheit, most of the world uses Celsius, and British cookbooks still use gas marks. Converting between them isn’t hard — the formulas are simple — but a wrong conversion is the fastest way to burn a cake or undercook a roast. This guide gives you the exact conversions, a quick reference table for common baking temperatures, and the mental math to do it on the fly.

The Two Conversion Formulas You Actually Need

• °F → °C: subtract 32, then multiply by 5/9. (350°F − 32) × 5/9 ≈ 177°C.
• °C → °F: multiply by 9/5, then add 32. (180°C × 9/5) + 32 = 356°F.

For a quick estimate, halve or double: °C ≈ (°F − 30) ÷ 2, and °F ≈ (°C × 2) + 30. It’s close enough for most recipes, but use the exact formula when baking precision matters.

Common Baking Temperatures: Quick Reference

Oven Setting	°F	°C	Gas Mark
Very slow / warming	250°F	120°C	½
Slow / low	300°F	150°C	2
Moderate / medium	350°F	177°C	4
Moderately hot	375°F	190°C	5
Hot	400°F	204°C	6
Very hot	425°F	218°C	7
Hottest (pizza, bread)	450-475°F	230-245°C	8-9

Gas Marks, Decoded

Gas marks are a British convention where each mark equals about 14°C (25°F) of increase, starting at Mark 1 = 275°F (135°C). A simple rule: gas mark × 14 + 121 ≈ °C. So Mark 4 → (4 × 14) + 121 = 177°C. Most recipes land between Mark 2 and Mark 7, which conveniently maps to the table above.

Practical Tips for Accurate Oven Work

• Know your oven’s reality: home ovens run 10-25°F (5-14°C) off their dial. An inexpensive oven thermometer is the best baking upgrade you can buy.
• Fan vs. conventional: convection/fan ovens cook faster — reduce the temperature by about 25°F (15°C) or shorten the time by 20-25%.
• Round sensibly: when converting, round to the nearest 5°C — ovens don’t hold exact temperatures anyway.
• Never convert while the oven is on: decide the target temperature before you preheat, so the oven stabilizes at the right setting.

Need to convert other units while cooking — weights, volumes, or pan sizes? The Temperature Converter at Today Calculator handles °F, °C, and Kelvin instantly, so you can double-check any recipe conversion in seconds.