Oven Temperature Converter: Celsius, Fahrenheit, Gas Mark and Fan

1. Pick the unit you are starting from: Celsius, Fahrenheit or UK gas mark. Most recipes use one of these three.
2. Type the temperature. For a gas mark, enter a number from 1 to 9 (or 0.25 for one quarter and 0.5 for one half). The answer updates as you type.
3. Read the conventional Celsius and Fahrenheit values, the nearest gas mark, and the fan-oven equivalent. Pick the decimal places if you want a rounded whole number.

In this guide deg C means degrees Celsius and deg F means degrees Fahrenheit. The tool itself shows the degree sign.

An oven temperature conversion restates the same heat setting in another unit. The heat does not change. Only the number and the label change. A cook needs it when a recipe and an oven speak different languages.

Three systems are in daily use. Most of the world sets ovens in degrees Celsius. The United States uses degrees Fahrenheit. Older British and many gas ovens use a gas mark, a dial numbered from 1 to 9 with two half steps below 1.

Only one of these three is tied to the others by an exact formula. Celsius and Fahrenheit convert with fixed numbers, so 180 deg C is always 356 deg F. The gas mark is a dial convention, not a formula, so each mark is matched to a rounded Celsius and Fahrenheit value by a standard chart.

This page converts the reading you give it. It does not know your oven, your rack height or your cookware, so treat the gas mark and fan values as a trusted starting point, not a guarantee. For the background story, see our oven temperature conversion guide.

The Celsius to Fahrenheit step stretches each Celsius degree to 1.8 Fahrenheit degrees, then adds 32 to line up the freezing points.

1. Multiply the Celsius value by 1.8. Example: 180 x 1.8 = 324.
2. Add 32. Example: 324 + 32 = 356 deg F.
3. Check by going back: (356 - 32) x 5/9 = 180 deg C.

The gas mark is different. There is no equation, only the fixed UK chart below, where Gas Mark 4 is set to 180 deg C and 350 deg F. The chart rounds to the marks a dial actually offers, so it does not always match the exact formula to the degree. That is why 180 deg C is exactly 356 deg F by formula, yet the gas chart and US ovens both call that setting 350.

The fan rule is also a convention, not physics: a fan oven is usually set about 20 deg C below the conventional Celsius value, because moving air heats food faster. For a single-scale tool, see the Celsius to Fahrenheit converter.

A recipe that says 180 deg C. 180 x 1.8 = 324, and 324 + 32 = 356 deg F. US ovens are set to 350 deg F, and this is Gas Mark 4. A fan oven would use 180 - 20 = 160 deg C. This is the classic moderate oven for cakes and biscuits.

A recipe that says 350 deg F. (350 - 32) x 5/9 = 177 deg C, usually rounded to 175 or 180 on a Celsius dial. It is still Gas Mark 4. A fan oven would use about 157 deg C, set as 155 or 160.

A recipe that says Gas Mark 6. On the fixed UK chart that is 200 deg C and 400 deg F, a moderately hot oven for roasting and pastry. A fan oven would use 200 - 20 = 180 deg C.

A high-heat example: Gas Mark 9. That is 240 deg C and 475 deg F, a very hot oven for bread and pizza. Many home ovens stop near this point. Reading from Fahrenheit instead? Start with the Fahrenheit to Celsius converter.

A conventional oven heats mostly from elements at the top and bottom. A fan oven, also called convection, adds a fan that pushes hot air around the cavity, so food cooks faster and more evenly.

To use a conventional recipe in a fan oven, the common rule is to drop the Celsius setting by about 20, or to go down one gas mark. So a conventional 180 deg C becomes a fan 160 deg C, and a conventional Gas Mark 6 becomes roughly Gas Mark 5.

The 20 deg C figure is a rounded rule of thumb. Some manufacturers suggest 15, others 25, and a Fahrenheit recipe is often cut by about 25 deg F instead. Always check your oven manual, and use an oven thermometer for anything delicate.

The formula is fixed, but several things decide whether the setting works for your bake.

Fan or Conventional

The single biggest factor. A fan oven set to the conventional number will run hot and can overbake the outside before the middle is done. Drop by about 20 deg C.

Oven Accuracy

Home ovens often read 10 to 20 degrees off the dial, and the back is usually hotter than the door. A cheap oven thermometer tells you the true temperature.

Which Chart You Trust

Gas-mark charts agree on the higher marks but differ a little at Gas Mark 1 to 3, where some list 150 or 160 deg C instead of 170. This tool uses one common UK chart. Your recipe may use another.

Rounding to the Dial

The exact answer is often not a mark you can set. 177 deg C is really 350 deg F, yet a Celsius dial offers 175 or 180. Pick the nearest mark and watch the bake.

The standard UK gas-mark chart used by this tool. The Celsius and Fahrenheit columns are the common dial values, and the fan column is the conventional Celsius value minus 20.

Treat the gas-mark rows as a common convention, not an exact law. For the pure scale math on its own, see the Celsius to Fahrenheit formula guide.

Cooking from a Foreign Recipe

A US recipe in Fahrenheit, a European one in Celsius or a classic British one in gas marks all point at the same heat. Convert once and set your dial.

Switching Ovens

Moved from a conventional oven to a fan one, or the reverse? Convert the recipe setting to match the oven you now have.

Replacing an Old Cooker

New ovens are marked in Celsius, while a lifetime of recipes may be in gas marks. The chart bridges the two.

Teaching and Conversions

The exact formula makes this a tidy worked example for the Celsius and Fahrenheit scales, with the gas mark as a real-world rounding case.

1. Using a Conventional Number in a Fan Oven

Setting a fan oven to 200 deg C for a recipe that means a conventional 200 deg C bakes about 20 degrees too hot. Drop to 180.

2. Adding 32 Before Multiplying

(180 + 32) x 1.8 gives 381.6. The correct answer is 356. Multiply by 1.8 first, then add 32.

3. Expecting the Gas Chart to Match the Formula Exactly

180 deg C is 356 deg F by formula, but the chart and US ovens call it 350. Both are correct for their purpose.

4. Confusing a Gas Mark with a Temperature

Gas Mark 6 is not 6 degrees. It is 200 deg C. Enter 6 with the unit set to gas mark.

5. Ignoring the Oven Itself

Even a perfect conversion fails if the oven runs hot or cold. Check with a thermometer for anything that matters.

The Celsius to Fahrenheit conversion is exact. The gas-mark and fan values are common conventions and are only as precise as the chart and the rule allow.

180 deg C is exactly 356 deg F by formula, which ovens set as 350 deg F, and it is Gas Mark 4. In a fan oven you would use about 160 deg C.

350 deg F is (350 - 32) x 5/9 = 177 deg C, usually rounded to 175 or 180 on a Celsius dial. It is Gas Mark 4.

On the standard UK chart, Gas Mark 6 is 200 deg C or 400 deg F, a moderately hot oven. A fan oven would use about 180 deg C.

Lower the Celsius setting by about 20, or go down one gas mark. A conventional 200 deg C becomes a fan 180 deg C. Ovens vary, so check your manual.

356 deg F is the exact formula answer. The gas chart and US ovens round to 350 because dials move in 25-degree steps. Both are right for their use.

No. A gas mark is a dial number, not degrees. Gas Mark 1 is about 140 deg C and Gas Mark 9 is about 240 deg C. Set the unit to gas mark before you enter it.

It is a common rounded rule. Some makers suggest 15 or 25 degrees, and Fahrenheit recipes are often cut by about 25 deg F. Treat it as a close starting point.

They agree on the higher marks but differ slightly at Gas Mark 1 to 3. This tool uses one common UK chart. Your recipe might list a slightly different Celsius value.

Most home ovens top out near 240 to 260 deg C, which is Gas Mark 9 to 10 and about 475 to 500 deg F. That is the range for bread and pizza.

No. The math runs in your browser. Anything you Save stays in your own browser storage until you clear it.

• Exact Celsius, Fahrenheit and kelvin temperature conversion relations (NIST SP 811, Appendix B.9).
• Touchstone temperatures and approximate oven equivalences (NIST Office of Weights and Measures).
• Oven temperature conversion table with gas marks and fan settings (Which?, UK consumer body).
• Celsius, Fahrenheit, fan and gas-mark oven conversion chart (Flawless Food, UK cookery reference).