Convert gas mark to celsius instantly. Enter a value below, or use the formula and reference table further down the page.
In practice
Gas mark is the numbered oven scale on UK and Irish cookers, so recipes from the BBC, Mary Berry or any British cookbook often list it instead of degrees. It is not a formula: it is a lookup table. A common one is mark ¼ = 110°C, ½ = 120°C, 1 = 140°C, 2 = 150°C, 3 = 160°C, 4 = 180°C, 5 = 190°C, 6 = 200°C, 7 = 220°C, 8 = 230°C and 9 = 240°C. Gas mark 4 is the everyday 'moderate' oven, equal to 350°F. Those temperatures are for conventional ovens; for a fan oven take about 20°C off, and since individual cookers can run hot or cool, an oven thermometer is worth having when a bake is fussy.
How to convert gas mark to celsius
Multiply by 14, then add 121.
°C = (gas mark × 14) + 121Example: 10 gas mark = 261 °C.
Gas Mark to Celsius conversion table
| Gas Mark (gas mark) | Celsius (°C) |
|---|---|
| 1 gas mark | 135 °C |
| 2 gas mark | 149 °C |
| 3 gas mark | 163 °C |
| 4 gas mark | 177 °C |
| 5 gas mark | 191 °C |
| 10 gas mark | 261 °C |
| 15 gas mark | 331 °C |
| 20 gas mark | 401 °C |
| 25 gas mark | 471 °C |
| 50 gas mark | 821 °C |
| 100 gas mark | 1521 °C |
Frequently asked questions
How many celsius is 1 gas mark?
1 gas mark equals 135 celsius.
What is the formula to convert gas mark to °C?
To convert gas mark to °C, multiply by 14 and add 121. The full formula is: °C = (gas mark × 14) + 121.
How do I convert celsius back to gas mark?
Use the same calculator above and type your value into the celsius field instead — it converts in both directions. Or use the reverse formula: gas mark = (°C − 121) ÷ 14.
Is the gas mark to °C conversion exact?
The conversion factor used here (14) is the standard internationally defined value. Results on this page are rounded to four decimal places for readability.