Are fan-assisted ovens different?

Yes — most recipes recommend reducing fan-oven temperatures by about 20°C (or 25°F) compared to conventional. Some recipes already adjust, so check your recipe's note before adjusting again.

Why are Gas Marks fractional below 1?

Pre-1980s gas ovens couldn't reliably hold low temperatures, so the 1/4 and 1/2 marks were introduced for dehydrating fruit, slow-roasting, and overnight cooking. Modern recipes use them rarely.

Does the calculator handle gas marks above 9?

No — Gas Mark 9 (≈475°F / 246°C) is the practical maximum on home ovens. Commercial pizza ovens go higher but use separate calibration.

Does the calculator store my data?

No. All conversions run in your browser.

Oven Temperature Converter

°C ↔ °F ↔ Gas Mark, with the standard table built in.

Three temperature scales coexist in home cooking: Celsius on the metric side, Fahrenheit on US ovens, and UK Gas Mark on a half-century of British recipes. The widget below converts any of the three to the other two, with the standard Gas Mark table (Mark 1 = 275°F = 135°C, then 25°F per mark up to Mark 9) baked in.

Fahrenheit

°F

350°

°C

177°

Gas Mark

moderate oven

How to use

Pick your starting scale
°F, °C, or Gas Mark — whichever your recipe uses.
Enter the value
Numeric input for °F and °C; a dropdown for Gas Mark with values from 1/4 to 9.
Read the other two
The widget always shows all three. The highlighted box is your input scale.

Standard oven temperatures

Description	°F	°C	Gas Mark
Very slow	250	120	1/2
Slow	300	150	2
Moderate	350	180	4
Moderately hot	400	200	6
Hot	425	220	7
Very hot	475	246	9

Frequently asked questions

Are fan-assisted ovens different?: Yes — most recipes recommend reducing fan-oven temperatures by about 20°C (or 25°F) compared to conventional. Some recipes already adjust, so check your recipe's note before adjusting again.
Why are Gas Marks fractional below 1?: Pre-1980s gas ovens couldn't reliably hold low temperatures, so the 1/4 and 1/2 marks were introduced for dehydrating fruit, slow-roasting, and overnight cooking. Modern recipes use them rarely.
Does the calculator handle gas marks above 9?: No — Gas Mark 9 (≈475°F / 246°C) is the practical maximum on home ovens. Commercial pizza ovens go higher but use separate calibration.
Does the calculator store my data?: No. All conversions run in your browser.

About

Where Gas Mark comes from

Introduced in the 1940s by British gas appliance makers to standardise oven dials. The numbering moves up in roughly 25°F (14°C) steps; it was deliberately disconnected from a physical temperature to discourage people from second-guessing the calibration.

Rounding policy

Output is rounded to whole degrees because oven thermostats are accurate to about ±10°F at best. Recipes don't need sub-degree precision.