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One oven, four ways to describe it
A British recipe says 180 °C fan. An American one says 375 °F. A handed-down card says gas mark 4. They may all describe similar heat, but getting from one to another involves a formula, an adjustment for fan ovens and a lookup table for gas marks. This converter takes any of them and shows every equivalent at once.
It is for anyone cooking from recipes written in another country, or with a different kind of oven from the one they own.
Why fan ovens run cooler settings
A fan oven, called a convection oven in the US, blows hot air around the food. Moving air carries heat into a cake or loaf faster than still air, so the same dial setting cooks more fiercely. Recipes compensate by lowering the temperature.
British recipes usually drop by 20 °C for fan, and American recipes by 25 °F for convection. They are close but not identical: 25 °F is about 14 °C. The converter uses each country’s own convention, so a UK fan figure and a US convection figure for the same dish can differ by a few degrees.
Converting a temperature
- Type the number into Temperature or gas mark. Gas marks can be entered as ¼, 1/2 or 0.5.
- Under The recipe says, choose what the recipe gives: °F, conventional oven, °C, conventional oven, °C, fan oven, °F, convection oven or Gas mark.
The results show Conventional, °C, Conventional, °F, Fan oven, °C, Convection, °F and Gas mark, plus a line Rounded for an oven dial for ovens that only click in steps.
From a British recipe to any oven
A sponge recipe from the UK says 180 °C fan. Choose °C, fan oven and enter 180. The converter shows:
- Conventional, °C: 200 °C
- Conventional, °F: 392 °F
- Fan oven, °C: 180 °C
- Convection, °F: 367 °F
- Gas mark: 6
- Rounded for an oven dial: 200 °C / 400 °F
So a conventional oven in the US would be set to 400 °F.
An American muffin recipe at 375 °F reads 191 °C conventional, 171 °C fan, 350 °F convection and gas mark 5, rounded to 190 °C on a dial.
Gas mark 3 comes out at 325 °F and 163 °C, or 143 °C in a fan oven. A loaf of bread baked at 450 °F sits at 232 °C, 212 °C fan, 425 °F convection and gas mark 8.
How gas marks work
Gas marks follow a simple British scale. Mark 1 is 275 °F, and each step adds 25 °F, up to mark 10 at 500 °F. Below mark 1 there are two half steps: ½ at 250 °F and ¼ at 225 °F. The converter finds the nearest mark for any temperature and tells you when a setting falls below ¼ or above 10.
Getting your oven right
- Buy an oven thermometer. Many home ovens run 10 to 20 degrees hot or cold, and no conversion can fix a dial that is wrong.
- Preheat fully. Most ovens need 15 to 20 minutes, and a stone or Dutch oven for bread needs much longer.
- Check early after a switch. Moving between fan and conventional changes browning as well as heat, so look a few minutes before the recipe’s time.
- Keep baking times in mind when you change pans. The cake pan size converter covers the effect of a different tin.
- Converting ingredients as well as heat? Use the cups to grams converter for dry goods, and the butter converter for sticks and blocks.
Oven questions
Should I always lower the temperature for a fan oven?
If the recipe was written for a conventional oven, usually yes. If it already gives a fan temperature, use it as written. Some modern fan ovens adjust automatically, so check your manual.
Why does the converter give 177 °C for 350 °F when recipes say 180 °C?
177 °C is the exact conversion. Recipes round to the nearest 10 °C, which is what the dial line shows. The difference is smaller than most ovens’ own error.
Is gas mark 4 really 350 °F?
Yes, on the standard scale gas mark 4 equals 350 °F, about 177 °C. Individual gas ovens can vary, as electric ones do.
What about bread in a Dutch oven?
Convert the temperature the same way, and follow the recipe on whether the fan should be on. While the lid is on, the pot shields the loaf from the moving air, so the fan matters most once the lid comes off.