Oven temperature converter

350 °F is 176.7 °C, which recipes print as 180 °C. In a fan oven that becomes 160 °C, and on a gas cooker it is gas mark 4. Type the temperature your recipe gives, choose the scale it uses, and the converter shows the same heat in Fahrenheit, Celsius, fan and gas mark.

Last updated 5 October 2026. Published by AUSSIE-AI LTD. How we check the numbers

The formulas

celsius = (fahrenheit minus 32) x 5 / 9

fahrenheit = celsius x 9 / 5 + 32

Those two are exact. The rest are conventions:

Rounded Celsius. Recipes print oven temperatures in steps of 10 °C, so 176.7 °C becomes 180 °C and 218.3 °C becomes 220 °C. The converter shows both the rounded figure and the exact one.
Fan ovens. A fan oven blows hot air around the food and cooks faster at the same setting, so recipes tell you to set it lower. The usual reduction is 20 °C, the figure Nigella Lawson's site gives, along with the advice to check the oven's manual. The converter uses 20 °C and lets you change it.
Gas marks. Gas mark 1 is 275 °F, and each mark adds 25 °F up to gas mark 9 (475 °F). Below 1 the scale halves: gas mark 1/2 is 250 °F and 1/4 is 225 °F. For a Celsius or Fahrenheit setting between two marks, the converter picks the nearest mark and says so.

Gas mark chart

Gas mark, Fahrenheit, Celsius and fan oven
Gas mark	°F	°C exact	°C as recipes print it	Fan °C (20 lower)
1/4	225	107.2	110	90
1/2	250	121.1	120	100
1	275	135	140	120
2	300	148.9	150	130
3	325	162.8	160	140
4	350	176.7	180	160
5	375	190.6	190	170
6	400	204.4	200	180
7	425	218.3	220	200
8	450	232.2	230	210
9	475	246.1	250	230
10	500	260	260	240

Gas mark 3 deserves a note: 325 °F is 162.8 °C, which rounds to 160 °C, but the conversion table on Wikipedia's gas mark page lists gas mark 3 as 170 °C. The two are 10 °C apart, so if a recipe gives both, follow the one it was tested with.

What the old recipe words mean

Older recipes describe heat instead of giving a number. NIST's metric kitchen gives these ranges:

Recipe says	°F	°C
Very slow	250	120
Slow	300 to 325	150 to 160
Moderately slow	325 to 350	160 to 180
Moderate	350 to 375	180 to 190
Moderately hot	375 to 400	190 to 200
Hot	400 to 450	200 to 230
Very hot	450 to 500	230 to 260

Your oven's dial and the real temperature

A dial setting and the air temperature inside the oven are not the same thing. NIST's metric kitchen notes that every oven, even of the same model, has its own temperature differences. For thermometers, NIST suggests checking a thermometer against boiling water, which is 100 °C at sea level, and correcting by the difference. An oven thermometer on the middle shelf tells you what the dial cannot.

Questions people ask

What is 350 °F in Celsius?

176.7 °C exactly. Recipes print it as 180 °C, which is 160 °C in a fan oven and gas mark 4.

How do I convert F to C quickly?

Subtract 32, then halve, then add a tenth of the result. 350 °F: 350 minus 32 is 318, half is 159, plus 15.9 gives 174.9, close to the exact 176.7. The exact formula is (F minus 32) x 5 / 9.

How do I convert C to F easily?

Double it and add 30 for a rough figure. 180 °C x 2 + 30 = 390 °F, against an exact 356 °F, so this shortcut runs high at oven temperatures. For baking use the exact formula: C x 9 / 5 + 32.

What is 200 °C in a fan oven?

180 °C fan, using the usual 20 °C reduction. In Fahrenheit, 200 °C is 392 °F, close to gas mark 6.

Is 180 °C the same as gas mark 4?

Yes, to the precision ovens work at. Gas mark 4 is 350 °F, which is 176.7 °C.

What is 140 F in C?

60 °C exactly: (140 minus 32) x 5 / 9 = 60.

Why does the US use Fahrenheit?

Everyday US measures were never switched to metric, so US oven dials and recipes are still marked in Fahrenheit. Most other countries print Celsius, and the UK and Ireland also kept gas marks on gas cookers.