What is gas mark and where is it used?

Gas mark is a numbered scale (typically 1/4 through 9) used on older and some current UK gas ovens, where each whole step corresponds to roughly a 25°F (about 14°C) increase. It remains common in UK cookbooks even on ovens that display temperatures in Celsius.

Should I use the exact or rounded conversion for baking?

Use the rounded conversion shown in recipes (e.g., 180°C = 350°F) rather than the mathematically exact figure (356°F) — these rounded values are what recipe writers and oven dial markings are calibrated to, and the small difference is within the normal variance of home ovens.

Oven Temperature Conversion Chart: Gas Mark, Celsius, and Fahrenheit

Convert oven temperatures between gas mark, Celsius, and Fahrenheit, including fan/convection oven adjustments, for recipes from any region.

Convert from

Celsius (°C) value

Convert to

Fahrenheit (°F): 225

Oven Temperature Conversion Chart: Gas Mark, Celsius, and Fahrenheit
Gas Mark	Celsius (°C)	Fahrenheit (°F)	Fan/Convection (°C)	Description
1/4	110	225	90	Very low / warming
1/2	120	250	100	Very low
1	140	275	120	Low
2	150	300	130	Low
3	160	325	140	Moderately low
4	180	350	160	Moderate
5	190	375	170	Moderately hot
6	200	400	180	Hot
7	220	425	200	Hot
8	230	450	210	Very hot
9	240	475	220	Very hot

How to Measure

If your oven has a fan/convection setting, use the Fan column directly, or reduce a conventional-oven temperature by about 20°C (or one gas mark) when using fan mode. Always check your oven's manual, since fan adjustments vary slightly by manufacturer.

Notes

These figures are the standard rounded values used by recipe writers and oven manufacturers, not exact mathematical conversions — for example, 180°C converts exactly to 356°F, but recipes treat 180°C and 350°F as equivalent because home ovens don't hold temperature precisely enough for the 6°F difference to matter.

Frequently Asked Questions

Source: Standard UK/European cookbook and oven manufacturer conversion tables · see our methodology