Gas Mark Converter
Enter an oven temperature in gas mark, Fahrenheit, or Celsius to convert instantly between all three — useful when following a UK recipe on an oven that only displays Fahrenheit or Celsius.
How the Gas Mark Converter formula works
Gas mark follows a roughly linear relationship with Fahrenheit across its standard range:
Fahrenheit ≈ 25 × Gas Mark + 250 Celsius = (Fahrenheit − 32) × 5/9
This approximation holds well for gas marks 1 through 9, the range used by most recipes.
Step-by-step calculation
- Multiply the gas mark number by 25 and add 250 to estimate the Fahrenheit equivalent.
- Convert Fahrenheit to Celsius using the standard formula, or convert directly using a reference chart for marks below 1.
Worked example
Gas mark 4 (a common baking temperature): Fahrenheit ≈ 25×4 + 250 = 350°F. Celsius = (350−32) × 5/9 ≈ 177°C — commonly rounded to 180°C on UK oven dials.
Frequently asked questions
Why do UK recipes use gas mark instead of a temperature?
Gas mark is a longstanding oven temperature scale historically tied to gas oven regulator settings in the UK and some Commonwealth countries, and it remains common in British recipes and cookbooks even though most modern ovens also display Fahrenheit or Celsius.
Is the gas mark to Fahrenheit relationship exact?
It's a close, commonly used approximation for marks 1 through 9 — some published conversion charts round slightly differently at certain marks, so minor variation between sources is normal and rarely affects baking results meaningfully.