Oven Temperature Calculator
Convert oven temperatures between Celsius, Fahrenheit, gas mark and fan.
Please note: Cooking guides only. Times and temperatures vary with oven calibration, altitude, starting temperature and cut. For anything where safety matters — poultry, pork, sous vide, preserving — use a probe thermometer and follow your national food safety guidance rather than a calculated time.
What the Oven Temperature Calculator does
Recipes quote oven temperatures in three incompatible systems, and fan ovens add a fourth complication by running effectively hotter than the dial. Converting means picking a reference — the conventional Celsius setting — and expressing everything else relative to it.
Formula
°F = °C × 9 ÷ 5 + 32°C = (°F − 32) × 5 ÷ 9Fan setting = Conventional − 20 °CGas mark 4 = 180 °C = 356 °F
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Temperature | number | Yes | — |
| Scale | one of 3 options | Yes | — |
| Your oven is | one of 2 options | Yes | — |
| Fan reduction | °C | Optional | Most fan ovens run 20 °C hotter than the dial suggests. Accepts 0 or more. |
How to use it
- Choose Scale and Your oven is.
- Enter Temperature.
- Optionally add Fan reduction.
- Select Calculate.
Worked example
A recipe calling for 180 °C in a conventional oven.
- Temperature
- 180
- Scale
- Celsius
- Oven
- Conventional
180 °C is 356 °F and gas mark 4. In a fan oven, set it to 160 °C instead.
Frequently asked questions
Why do fan ovens need a lower setting?
Moving air transfers heat far more efficiently than still air, so food at the same dial temperature cooks faster and browns harder. Dropping 20 °C compensates.
How accurate are gas marks?
Approximate. The steps are roughly 14 °C apart at the top of the range and 10 °C at the bottom, and individual ovens vary by more than that anyway.
Method and sources
Method. Exact conversion between Celsius, Fahrenheit and gas mark, with fan and conventional oven equivalents.
Assumptions
- The fan adjustment follows the common convention of roughly 20 °C lower than a conventional setting.
Limitations
- Celsius and Fahrenheit convert exactly; gas marks and fan equivalents are conventions and ovens vary around them.
- Domestic ovens commonly run 10–20 °C away from their dial, and the difference is not constant across the range — an oven thermometer settles it where the setting matters.
Sources
- None for the temperature conversion, which is exact arithmetic — Not applicable. The Celsius-Fahrenheit relationship. The fan and gas-mark equivalents are conventions, and are described as such rather than cited.