Nothing derails a bake faster than a recipe in the wrong temperature scale, whether it lists Fahrenheit and your oven shows Celsius, or it calls for a gas mark you have never used. An oven temperature conversion clears it up in seconds. This guide gives you the exact formula between Celsius and Fahrenheit, a full conversion chart including gas marks, and the one adjustment fan (convection) ovens need. With these, you can follow any recipe from any country with confidence. For quick conversions of any measurement, our unit converter is always on hand, and it pairs well with converting the ingredients too.
Quick answer: To convert oven temperature from Celsius to Fahrenheit, multiply by 9/5 and add 32, so 180C is 356F (usually rounded to 350F). Gas mark 4 equals 180C / 350F, a common moderate baking temperature. For a fan oven, reduce a conventional temperature by about 20C.
Celsius and Fahrenheit formula
The two temperature scales are linked by a simple formula that both scales and shifts, because they start at different points.
Fahrenheit = (Celsius x 9/5) + 32
Celsius = (Fahrenheit – 32) x 5/9
For example, 180 degrees Celsius is (180 x 9/5) + 32 = 324 + 32 = 356 degrees Fahrenheit, which recipes usually round to 350. Cookbooks round oven temperatures to convenient numbers, so small differences are normal and fine.
Full conversion chart
This chart covers the temperatures you will meet in most recipes:
| Celsius | Fahrenheit | Gas mark | Description |
|---|---|---|---|
| 140 C | 275 F | 1 | Very cool |
| 150 C | 300 F | 2 | Cool |
| 170 C | 325 F | 3 | Warm |
| 180 C | 350 F | 4 | Moderate |
| 190 C | 375 F | 5 | Moderately hot |
| 200 C | 400 F | 6 | Hot |
| 220 C | 425 F | 7 | Hot |
| 230 C | 450 F | 8 | Very hot |
Convert anything in the kitchen
Our unit converter handles temperature and more, and our guide on cooking conversions covers turning cups into grams and millilitres so the whole recipe works.
Understanding gas marks
Gas marks are a temperature scale used on many gas ovens, especially in the UK. Gas mark 1 is about 140 degrees Celsius (275 Fahrenheit), and each step up adds roughly 25 degrees Fahrenheit, or about 14 degrees Celsius. Gas mark 4, at 180 degrees Celsius or 350 Fahrenheit, is the everyday moderate baking temperature you will see most often.
If your recipe gives a gas mark and your oven shows Celsius or Fahrenheit, the chart above translates it directly.
Fan oven adjustment
Fan ovens, also called convection ovens, circulate hot air and cook more efficiently, so they run effectively hotter than conventional ovens at the same setting. The standard adjustment is to reduce a conventional temperature by about 20 degrees Celsius, or roughly one gas mark, when using a fan oven.
So a recipe calling for 180 degrees Celsius in a conventional oven becomes about 160 degrees in a fan oven. Check your appliance manual, as some already state fan temperatures.
Frequently asked questions
How do I convert oven temperature from Celsius to Fahrenheit?
Multiply the Celsius temperature by 9/5, then add 32. For example, 180 degrees Celsius is (180 times 9/5) plus 32, which is 356 degrees Fahrenheit, usually rounded to 350 in recipes. To go the other way, subtract 32 from the Fahrenheit temperature, then multiply by 5/9 to get Celsius.
What is gas mark 4 in Celsius and Fahrenheit?
Gas mark 4 is about 180 degrees Celsius or 350 degrees Fahrenheit. It is a moderate oven temperature and one of the most common settings in baking, used for many cakes, biscuits, and roasts. Each gas mark up or down changes the temperature by roughly 25 degrees Fahrenheit, or about 14 degrees Celsius.
How much do I reduce the temperature for a fan oven?
Reduce a conventional oven temperature by about 20 degrees Celsius, or roughly one gas mark, for a fan (convection) oven, because circulating air cooks more efficiently. So 180 degrees Celsius conventional becomes about 160 degrees fan. Some recipes and ovens already state fan temperatures, so check before adjusting to avoid reducing twice.
What is 350 F in Celsius?
350 degrees Fahrenheit is about 180 degrees Celsius, which is gas mark 4. Using the formula, (350 minus 32) times 5/9 is 176.7, which recipes round to 180. This is the standard moderate baking temperature, so it is a useful one to remember when converting between the two scales.
Why are converted oven temperatures rounded?
Because ovens are not precise to the degree, and round numbers are easier to set and remember. The exact conversion of 180 Celsius is 356 Fahrenheit, but recipes use 350 for convenience. These small roundings do not affect baking results, since a few degrees either way makes no meaningful difference in a home oven.
The bottom line
To convert oven temperature, multiply Celsius by 9/5 and add 32 for Fahrenheit, so 180C is about 350F, which is gas mark 4, the standard moderate setting. Use the chart to translate any Celsius, Fahrenheit, or gas mark, and remember to reduce by about 20C for a fan oven. Small roundings are normal and harmless. For any kitchen conversion, use our unit converter.
Further reading
For authoritative background on this topic, see Gas mark on Wikipedia.
Note. This article is for general informational purposes. Oven behaviour varies; use an oven thermometer and follow your appliance manual for best results.
Last reviewed: July 2026