Oven temperature conversion: Celsius, Fahrenheit and gas marks
What 150 °C, 180 °C and 200 °C are in Fahrenheit, which gas mark is which, what “fan” changes, and why the number on the dial is often meaner than the number in the recipe.
By Akash Yadav Updated 19 October 2026
The problem
Four ways of saying the same temperature
A recipe for the same bake might say 180 °C, 350 °F, gas mark 4, or 160 °C fan. All four are the temperature the recipe wants — they differ in where the recipe was written. Celsius is used almost everywhere, Fahrenheit in the United States, gas marks on British and Irish gas ovens, and a "fan" figure wherever the oven moves air around with a fan.
Nothing about that is complicated: the Celsius↔Fahrenheit part is the ordinary conversion, and the Celsius to Fahrenheit converter shows the arithmetic. What catches people out is the second layer — ovens are sold with dials marked in steps, and recipes are written for dials, so the number in the recipe and the exact conversion of it are rarely the same figure.
Settings
Oven temperatures in Celsius and Fahrenheit
These are the settings recipes actually call for, converted exactly. The third column is what a Fahrenheit dial will offer you instead.
| Setting | In Fahrenheit | Nearest dial mark |
|---|---|---|
| 120 °C | 248 °F | 250 °F |
| 140 °C | 284 °F | 275 °F |
| 150 °C | 302 °F | 300 °F |
| 160 °C | 320 °F | 325 °F |
| 170 °C | 338 °F | 350 °F |
| 180 °C | 356 °F | 350 °F |
| 190 °C | 374 °F | 375 °F |
| 200 °C | 392 °F | 400 °F |
| 220 °C | 428 °F | 425 °F |
| 230 °C | 446 °F | 450 °F |
| 240 °C | 464 °F | 475 °F |
The Fahrenheit column is exact; a Fahrenheit oven can only be set to 25 °F marks, so 180 °C is dialled as 350 °F. A Celsius oven has the easier job: 350 °F is the 180 °C mark, and dials are graduated in 10 °C steps.
Fan
Fan ovens: set about 20 °C lower
A fan oven (convection oven, fan-assisted, or "fan forced" in Australia) moves hot air across the food instead of letting it sit, so the same dial setting cooks faster and browns harder. The usual guidance is to set it 20 °C lower than the conventional figure the recipe gives.
| Conventional | °F | Fan oven | °F |
|---|---|---|---|
| 150 °C | 302 °F | 130 °C | 266 °F |
| 160 °C | 320 °F | 140 °C | 284 °F |
| 170 °C | 338 °F | 150 °C | 302 °F |
| 180 °C | 356 °F | 160 °C | 320 °F |
| 190 °C | 374 °F | 170 °C | 338 °F |
| 200 °C | 392 °F | 180 °C | 356 °F |
| 220 °C | 428 °F | 200 °C | 392 °F |
Appliance manuals do not agree on the exact figure — some say 20 °C, some 25 °C (and in Fahrenheit, about 25 °F) — because it depends on the oven. Treat it as a starting point, and if your oven has a conventional/fan switch, let it do the adjustment instead. If it is an air fryer rather than a fan oven, the adjustment is larger; the air fryer guide has it.
Gas
Gas marks, in both scales
Gas marks are the dial numbers on gas ovens in the UK and Ireland. The scale is defined in Fahrenheit — 25 °F per mark — and the Celsius column is the rounded value recipes print, which is why conventional tables disagree about the coldest mark.
| Gas mark | °F | °C | Description |
|---|---|---|---|
| ¼ | 225 °F | 110 °C | Very slow |
| ½ | 250 °F | 120 °C | Very slow |
| 1 | 275 °F | 140 °C | Slow |
| 2 | 300 °F | 150 °C | Slow |
| 3 | 325 °F | 170 °C | Moderately slow |
| 4 | 350 °F | 180 °C | Moderate |
| 5 | 375 °F | 190 °C | Moderately hot |
| 6 | 400 °F | 200 °C | Moderately hot |
| 7 | 425 °F | 220 °C | Hot |
| 8 | 450 °F | 230 °C | Hot |
| 9 | 475 °F | 240 °C | Very hot |
Mark 4 — the setting most British baking recipes use — is 350 °F and 180 °C on a dial. Convert 180 °C exactly and you get 356 °F, which is what the round dial mark is standing in for. The same rounding runs through the scale: the arithmetic puts mark 1 at 135 °C, but dials and recipes print 140 °C. That one-step difference is normal and harmless, and it is the reason two conversion tables can both be right and still disagree.
Rounding
Why the dial and the recipe disagree anyway
A conversion gets your oven to within a dial step of the recipe; it cannot make the oven hold a temperature. A domestic oven thermostat switches the element on and off and lets the temperature swing around the setting, shelf position changes the heat the food actually meets, and opening the door drops the air temperature by tens of degrees.
So when a bake goes wrong, the conversion is rarely the cause. If your oven consistently runs hot or slow, an oven thermometer is a better investment than a more precise conversion — measure the swing once and you know it for every recipe afterwards.
Common questions
Oven conversions people actually ask about
What is 425 °F in a fan oven?
About 200 °C. 425 °F is 218 °C, which recipes round to 220 °C for a conventional oven, and a fan oven runs about 20 °C lower. It is gas mark 7. The Celsius to Fahrenheit converter will do any other figure, and the chart covers the whole range at a glance.
What is gas mark 4 in Celsius and Fahrenheit?
350 °F and 180 °C — the standard moderate setting for cakes, biscuits and roasting. Gas mark 5 is 375 °F and 190 °C, and each mark above that adds 25 °F (about 14 °C).
How do I follow a US recipe in a gas oven?
Translate the Fahrenheit figure to the nearest gas mark: 350 °F is mark 4, 400 °F is mark 6, 425 °F is mark 7. US recipes assume a conventional oven, so leave the fan out of it — and if your oven is fan-assisted, drop about 20 °C from the Celsius figure you looked up.
Why does my oven cook faster than the recipe says?
Almost always the oven rather than the conversion. Thermostats swing, dials drift, and fan ovens at the same dial setting are faster than conventional ones by design. If it happens every time, check the temperature with a thermometer and adjust the dial — the arithmetic here is exact, but it is describing the number on the dial, not the heat inside the oven.
If you want the reasoning behind the °C to °F step rather than the settings table, the formula guide works through it — and every factor involved is listed on the methodology page.
Use it
Converters in this guide
Every figure in this guide is computed at build time from the same conversion engine as the converters it links to, and the factors behind it are the defining standards listed on the methodology page. Nothing here is typed by hand from a template.
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