Oven temperature converter (°C, °F, fan and gas mark)

Convert an oven temperature from Celsius to Fahrenheit with the fan-oven equivalent, or turn a UK gas mark into °C and °F — for recipes written for a different oven from yours.

Conventional oven temperature (°C)

Result

Temperature

Fan oven equivalent

How to use this tool

For a °C recipe, enter the conventional temperature to get °F and the fan-oven setting.
For a gas-mark recipe, switch to gas mark and choose the mark.
Use the fan figure only if your oven is fan-assisted and the recipe gives a conventional temperature.

Assumptions

The 20°C fan reduction is a widely used rule of thumb; some manufacturers recommend 10–20°C, so check your oven's manual.
Gas mark equivalents vary slightly between published tables and oven makers; the table above is the common UK reference.

Sources & reference data

NIST — SI units of temperature (Celsius and Fahrenheit)

Technical details: what the fields mean

Conventional oven temperature celsius: The conventional (non-fan) oven temperature from the recipe. If the recipe already says 'fan', don't reduce it again.

Methodology

°F = °C × 9⁄5 + 32, rounded to the nearest degree. Fan equivalent = conventional °C − 20, the usual UK recipe convention. Gas marks use the common UK reference table: 1 = 140°C, 2 = 150, 3 = 160, 4 = 180, 5 = 190, 6 = 200, 7 = 220, 8 = 230, 9 = 240.

Worked example

A UK recipe says 180°C

Inputs: Conventional oven temperature: 180°C

Result: 356°F (most American recipes would round to 350°F); 160°C in a fan oven.

Roasting at 220°C

Inputs: Conventional oven temperature: 220°C

Result: 428°F (often written as 425°F); 200°C fan.

An old recipe says gas mark 6

Inputs: Gas mark: 6

Result: 200°C, 392°F, or 180°C in a fan oven.

Practical guidance

American recipes round to the nearest 25°F (350, 375, 400, 425°F); the exact conversion lands a few degrees away, which makes no practical difference.
Oven thermostats are often 10°C or more out. An inexpensive oven thermometer tells you what your dial really means.
Gas ovens are hotter at the top than the bottom; recipes written for gas marks assume the middle shelf.

Common mistakes

Reducing for a fan oven when the recipe temperature is already a fan figure, which undercooks the bake.
Not reducing for a fan oven when the recipe is conventional, which can over-brown the outside before the middle is cooked.

FAQs

What is 180°C in Fahrenheit?

356°F — American recipes usually call this 350°F.

Should I adjust for a fan oven?

Yes, if the recipe gives a conventional temperature: fan ovens cook faster at the same setting, so the usual adjustment is about 20°C lower.

What is gas mark 4 in Celsius?

180°C (356°F), or 160°C in a fan oven.

Why doesn't gas mark go up evenly in °C?

Most marks are 10°C apart, but the jumps from 3 to 4 and from 6 to 7 are 20°C. It's a reference table, not a straight-line formula, so look the mark up rather than calculating it.

Last reviewed: 2026-09-25

Converts temperature scales and applies standard conventions; it can't account for your oven's thermostat accuracy, hot spots or shelf position.

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