🍳 Cooking & Baking

Oven Temperature Converter (°F, °C, Gas Mark, Fan)

Cross-convert any oven temperature between Fahrenheit, Celsius, fan-forced and gas marks, with meat doneness tables and high-altitude adjustments.

Built and maintained by Paul Clark, Redmoon Software · Checked against what this tool computes on August 26, 2026

Temperature

From

Oven type

Equivalent

— · — · Gas —

Fan-forced: — / — · Description: —

Description	°F	°C	Fan °C	Gas
Very cool	225	110	90	¼
Very cool	250	120	100	½
Cool	275	140	120	1
Cool	300	150	130	2
Warm	325	160	140	3
Moderate	350	180	160	4
Moderate hot	375	190	170	5
Hot	400	200	180	6
Hot	425	220	200	7
Very hot	450	230	210	8
Very hot	475	245	225	9
Searing	500	260	240	10

Meat doneness — internal temperature

Protein	Doneness	°F	°C
Beef / Lamb	Rare	125	52
Beef / Lamb	Medium-rare	135	57
Beef / Lamb	Medium	145	63
Beef / Lamb	Medium-well	150	66
Beef / Lamb	Well done	160+	71+
Pork	Medium (USDA safe)	145	63
Pork	Well done	160	71
Chicken / Turkey	Safe minimum	165	74
Chicken (dark thigh)	Best texture	175	79
Ground meats	Safe	160	71
Fish (most)	Flakes / opaque	145	63
Salmon / Tuna	Medium-rare	120	49
Veal	Medium	145	63

Quick reference

°C = (°F − 32) × 5/9. Fan-forced ovens cook faster: subtract ~20°C (40°F) from the conventional temperature, or reduce cooking time by 25%.

UK Gas Marks: ¼ = 110°C, ½ = 120°C, then each mark adds 10°C up to mark 9 = 240°C.

How it works

Everything is normalised to Celsius first. A Fahrenheit entry becomes (°F − 32) × 5/9, a Celsius entry passes straight through, and a Gas Mark entry is looked up in a fixed table where mark 1 is 140°C, 4 is 180°C and each step above adds 10°C to a maximum of 240°C at mark 9. The tool then converts back with °C × 9/5 + 32, picks whichever gas mark sits closest in Celsius, and labels the result with a description band from very cool up to searing.

The From selector decides how your number is read, and the eight presets from 200°F up to 500°F all switch it back to Fahrenheit. Oven type controls the headline figure while the separate Fan-forced line always reports your temperature minus 20°C, which is the number to use if your oven has a fan. The two reference tables below are static: gas mark equivalents on one, and safe or preferred internal meat temperatures on the other.

Fan compensation is a flat 20°C at every setting, so it is proportionally severe at low temperatures — a fifth off a 110°C dehydrate, but under a tenth off a 240°C roast. Note that 20°C is a 36°F difference, not the 40°F often quoted. Gas marks snap to the nearest whole entry, so intermediate temperatures round by up to 5°C, and nothing here corrects for altitude or for the fact that most domestic ovens run 10–15°C away from their dial.

Frequently asked questions

What is gas mark 4 in Celsius and Fahrenheit?

Gas mark 4 is 180°C, the most common baking temperature in British recipes. The chart pairs it with the everyday American 350°F, although the exact arithmetic conversion of 180°C is 356°F. The scale runs from mark 1 at 140°C in 10°C steps to mark 9 at 240°C.

How much should I lower the temperature for a fan oven?

By 20°C, which the Fan-forced line calculates for you. In Fahrenheit that is a 36°F drop, not the 40°F frequently quoted. As an alternative to dropping the temperature, keep it as written and cut the cooking time by roughly a quarter.

Can I enter gas mark one-quarter or one-half?

Not through the input box, which only accepts numbers and only matches whole marks 1 to 9. Read those two directly from the chart instead: gas mark one-quarter is 110°C or 225°F, and one-half is 120°C or 250°F.

What internal temperature should chicken reach?

The doneness chart gives 165°F, or 74°C, as the safe minimum for chicken and turkey. Dark thigh meat is listed separately at 175°F, or 79°C, because the connective tissue in it needs the extra heat to break down and taste tender rather than rubbery.

Why does my food cook faster than the chart suggests?

Dial settings are nominal. Domestic ovens commonly swing 10–15°C either side of the setpoint, and shelf position, tin colour and how full the oven is all change the effective heat. An oven thermometer on the middle shelf will tell you your own offset.

Fan ovens, and the offset that is only a convention

A fan-forced oven moves hot air over the food continuously, so heat transfers faster at the same air temperature. The standard adjustment is to drop the set temperature by about 20 °C — roughly 25 °F — when converting a conventional recipe, and that is the offset applied here.

It is a convention rather than a measurement. Some manufacturers state 15 °C, some 25, and some ovens apply the offset internally so the dial already reads the conventional-equivalent temperature. If your oven has both a fan and a conventional setting on the same dial, it almost certainly does not.

Gas marks and the dial that lies

Gas marks are a separate scale of their own, spaced roughly 25 °F apart from mark 1 upward, and converting to them always lands between marks for some temperatures. Rounding to the nearest mark is normal practice and is part of why gas ovens are more forgiving of imprecise recipes.

The larger point is that oven dials are frequently inaccurate by 10–20 °C, and the swing of a thermostat cycling on and off is wider than any conversion offset. An oven thermometer costs very little and tells you more than any conversion table can — if a recipe consistently runs fast or slow, the dial is the first suspect, not the recipe.