By Tim King · Updated 19 September 2026

Oven Temperature Converter

Celsius, Fahrenheit, Fan and Gas Mark

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How the Oven Temperature Converter works

Use this oven temperature converter when a recipe uses a different scale from your oven. 425 °F is 218 °C, which recipes round to 220 °C, 200 °C in a fan oven or gas mark 7. Type the temperature a recipe gives and say whether it is conventional Celsius, fan-forced Celsius, Fahrenheit or a gas mark. The page shows the same heat on all four scales, with the usual 20 °C reduction for a fan oven applied, and a full gas mark chart sits below for reference.

Oven temperature converter: one heat, four ways of saying it

A recipe is a set of instructions written for somebody else's kitchen. The ingredients translate easily; the oven line is where things go wrong. "Gas 4" means nothing on an electric range, "350 °F" means nothing on a European dial, and "180 °C" can be 20 degrees too hot if your oven has a fan and the writer's did not. This page takes the number you have, on whichever scale it came in, and shows the same heat on all four.

The formula behind each scale

Celsius to Fahrenheit: °F = °C × 9/5 + 32. Going back, °C = (°F − 32) × 5/9.
Fan-forced: fan °C = conventional °C − 20. The converter adds the 20 back before doing anything else when you enter a fan figure.
Gas mark to Fahrenheit: °F = 250 + 25 × mark for marks 1 to 10, so mark 1 is 275 °F and mark 10 is 500 °F. The fractional marks sit below that, with ½ at 250 °F and ¼ at 225 °F.
Fahrenheit to gas mark: the tool rounds (°F − 250) ÷ 25 to the nearest whole mark, caps it at 10, and returns ¼ or ½ between 212 and 262 °F. Anything under 212 °F reads "below ¼", with the heat word "Warming only".

Every entry goes to Fahrenheit first and then out to the other three, so any direction works.

Worked examples

Example 1: an American cookie recipe at 375 °F. (375 − 32) × 5/9 = 190.6, so the conventional setting is 191 °C and the fan setting 171 °C. On a UK dial, set 190 °C, or 170 °C fan. The gas mark is (375 − 250) ÷ 25 = 5, "moderately hot".

Example 2: an old British roast at gas 7 in a fan oven. Gas 7 is 250 + 175 = 425 °F, which is 218 °C conventional and 198 °C fan. Set the fan oven to 200 °C and expect the joint to be ready slightly sooner than the recipe says, because moving air strips the cool boundary layer from the meat's surface.

How many degrees is one gas mark? Each step is 25 °F, or about 14 °C. So a recipe that says "one mark lower" is asking for roughly a 15 °C drop, which is close to the fan adjustment. That is why many British cookbooks treat "fan" and "one mark down" as the same instruction. Conventional Celsius to fan, Fahrenheit and the gas mark this converter returns

Conventional °C	Fan °C	°F (exact)	Gas mark
100	80	212	¼
110	90	230	¼
120	100	248	½
130	110	266	1
140	120	284	1
150	130	302	2
160	140	320	3
165	145	329	3
170	150	338	4
175	155	347	4
180	160	356	4
185	165	365	5
190	170	374	5
195	175	383	5
200	180	392	6
210	190	410	6
220	200	428	7
230	210	446	8
240	220	464	9
250	230	482	9
260	240	500	10

The gas mark column is the nearest mark to the exact Fahrenheit value, so 160 °C lands on 3 and 170 °C on 4. Charts that round Celsius first can differ by one mark mid-range.

How to read the result

Conventional oven is the setting for an oven with top and bottom elements and no fan, and the figure most recipes assume.
Fan-forced (convection) is the same heat for an oven with a fan, 20 °C lower.
Fahrenheit is rounded to the whole degree. American recipes almost always use multiples of 25, so 356 °F will be written as 350.
Gas mark gives the mark and the traditional description, from "very slow" at ¼ and ½ to "extremely hot" at 10. Entering a gas mark outside ¼ to 10 shows "Gas marks run from ¼ to 10".

Where the numbers come from

Gas marks were introduced in Britain in the 1920s, when Radiation Ltd fitted its "Regulo" thermostat to the New World gas cooker, and the scale was defined in Fahrenheit. Fahrenheit is still the legal oven scale on US appliances and in US recipe publishing, while the UK, Ireland, Australia and New Zealand print Celsius with fan and gas equivalents side by side.

Tips and pitfalls

Check your oven. Domestic thermostats are commonly out by 10 to 25 °C. An oven thermometer on the middle shelf costs less than one ruined cake and tells you what the dial really means.
Fan does not mean faster for everything. Rich fruit cakes and custards still need their long, low bake; a fan oven at 20 °C less keeps them from over-browning, not from needing time.
Scaling changes time, not temperature. Doubling a recipe in a deeper tin needs longer, sometimes at 10 °C lower, never hotter. The recipe scaler adjusts the quantities.

For the ingredient lines of a foreign recipe, use cups to grams and tablespoons to grams. For any temperature outside the oven range, the Celsius to Fahrenheit converter gives the full scale.

Sources: Gas mark.

Checked against: 180 °C = 356 °F, gas mark 4

FAQ

What is 180 °C in Fahrenheit and gas mark?

180 °C is 356 °F, which recipes round to 350 °F, and gas mark 4. In a fan-forced oven set it to 160 °C. This is the standard moderate oven that most cakes, biscuits and casseroles are cooked in, and the most common temperature in recipe books.

What is gas mark 4 in Celsius?

Gas mark 4 is 350 °F, which is 177 °C and is always written as 180 °C in recipes. For a fan oven use 160 °C. Each gas mark above or below is a step of about 14 °C, so gas 5 is 190 °C and gas 3 is 170 °C, or 165 °C if you are being exact.

How much lower should I set a fan oven?

Twenty degrees Celsius lower than the conventional temperature, or roughly one gas mark or 35 °F. Some manufacturers suggest 10% rather than a fixed 20 °C, which comes to the same thing in the usual baking range. Cooking times are often a little shorter in a fan oven too, so check early.

What is 350 °F in Celsius?

350 °F is 177 °C, which rounds to 180 °C in a conventional oven, or 160 °C in a fan oven. It is gas mark 4. This is the standard American baking temperature and matches the moderate oven used for most cakes and cookies.

Does the recipe mean a fan oven or a conventional one?

If it does not say, assume conventional. Gas mark figures are always conventional, and American recipes in Fahrenheit almost always are too. Modern British and Australian recipes usually list both, as in "180 °C / 160 °C fan". If you only have a fan oven, drop the stated temperature by 20 °C.

Why are gas mark temperatures such odd numbers in Celsius?

Because gas marks were defined in Fahrenheit, 25 °F apart from 275 °F at mark 1. Converted exactly, mark 4 is 177 °C and mark 6 is 204 °C, and recipe books round them to 180 and 200 °C. The differences are smaller than the temperature swing of an ordinary oven thermostat.