Oven Temperature Converter
Convert oven temperatures between Celsius, Fahrenheit and gas mark — and between fan and conventional, which is the one most recipes forget to tell you.
The Celsius-to-Fahrenheit part is ordinary arithmetic.
How the oven temperature converter works
The Celsius-to-Fahrenheit part is ordinary arithmetic. Gas marks are not: they run in steps of about 14°C from gas 1 at 140°C, so they map onto round Celsius numbers only approximately, and every published chart rounds slightly differently.
The conversion that actually changes results is fan to conventional. A fan oven circulates air, so it cooks faster and more evenly at the same dial setting — the standard adjustment is to set a fan oven about 20°C below a conventional recipe, or equivalently to add 20°C when converting a fan recipe to a conventional oven. Get this backwards and a cake bakes at effectively 40°C off.
Formula: °F = °C × 9/5 + 32; gas mark ≈ (°C − 121) ÷ 14; fan ≈ conventional − 20°C
Worked examples
| Inputs | Conventional oven | Note |
|---|---|---|
| 180°C conventional | 180°C | 160°C fan, 356°F, gas mark 4 |
| 350°F | 177°C | 177°C — usually written as 180°C |
| Gas mark 6 | 205°C | 205°C, 185°C fan |
| 160°C fan | 180°C | equals 180°C conventional |
FAQFrequently asked questions
What is 180°C in Fahrenheit?
356°F, which recipes usually round to 350°F.
What is 180°C in a fan oven?
160°C. A fan oven circulates air and cooks faster, so set it about 20°C lower than a conventional recipe.
What is gas mark 4?
About 180°C or 350°F — the standard moderate oven.
Should I reduce the time as well as the temperature?
If you keep the conventional temperature in a fan oven, yes — reduce time by roughly 20%. It is simpler to drop the temperature by 20°C and leave the time alone.
Why do charts disagree slightly?
Because gas marks do not land on round Celsius numbers, so every chart rounds a little differently. Any of them is close enough for cooking.
Where these figures come from
- US FDA — Safe Minimum Internal Temperatures — the internal temperatures the roasting calculator targets
- NIST SP 811 — Guide for the Use of the International System of Units — the exact weight and volume conversions used throughout
- US Food and Drug Administration — food safety and labelling standards
Last checked: September 2026. Baking ratios follow standard baker's percentage practice; roasting guidance follows published safe internal temperatures.