What is fan oven?
A fan oven uses a fan to circulate hot air around the oven. In everyday UK cooking, fan temperatures are often set about 20°C lower than conventional oven temperatures.
A fan oven is an oven that uses a fan to move hot air around the cooking space. This usually helps heat circulate more evenly than in a conventional oven.
Because fan ovens spread heat more efficiently, many UK recipes use a lower fan temperature than the conventional Celsius temperature.
Why fan ovens matter
Many recipes show more than one oven temperature, such as 180°C / 160°C fan / gas mark 4. The fan number is the one to use if your oven has a fan-assisted setting.
Using the conventional temperature in a fan oven can sometimes cook food too quickly on the outside, especially for cakes, biscuits and roasted foods.
Fan oven vs conventional oven
A conventional oven mainly heats from fixed elements. A fan oven circulates heated air, which can make the oven feel hotter for the same Celsius setting.
| Oven type | How it heats | Practical effect |
|---|---|---|
| Conventional oven | Heat from oven elements without constant forced air | Often uses the higher temperature in recipe instructions |
| Fan oven | Fan circulates hot air around the oven | Often uses a temperature about 20°C lower |
Fan oven conversion rule
A common kitchen shortcut is to reduce a conventional oven temperature by about 20°C when using a fan oven. This is an estimate, not a perfect scientific rule.
fan temperature ≈ conventional Celsius temperature − 20°C
For example, 180°C conventional is often written as about 160°C fan.
Common fan oven conversions
Use these as everyday cooking guides. Ovens vary, so check the food near the end of the cooking time, especially when baking.
| Conventional oven | Fan oven estimate | Common gas mark |
|---|---|---|
| 140°C | 120°C fan | Gas mark 1 |
| 150°C | 130°C fan | Gas mark 2 |
| 170°C | 150°C fan | Gas mark 3 |
| 180°C | 160°C fan | Gas mark 4 |
| 190°C | 170°C fan | Gas mark 5 |
| 200°C | 180°C fan | Gas mark 6 |
| 220°C | 200°C fan | Gas mark 7 |
| 230°C | 210°C fan | Gas mark 8 |
| 240°C | 220°C fan | Gas mark 9 |
When you may need to adjust
The 20°C rule is useful, but it is not always enough. Your oven, tray position, food size and recipe type all matter.
- Baking: check cakes, biscuits and bread carefully because small changes can affect texture.
- Roasting: larger joints and vegetables may need timing adjustments as well as temperature changes.
- Frozen food: follow the packet instructions if they give a specific fan oven temperature.
- Older ovens: consider using an oven thermometer if results are often undercooked or overcooked.
How to convert to fan oven
The easiest method is to use the Oven Temperature Converter. For quick mental maths, reduce the conventional Celsius number by around 20°C.
- Find the conventional Celsius temperature in the recipe.
- Subtract about 20°C for a fan oven estimate.
- Use the nearest setting available on your oven.
- Check the food before the end of the suggested cooking time.
Quick answers
| Question | Practical answer |
|---|---|
| What is 180°C in a fan oven? | About 160°C fan |
| What is 200°C in a fan oven? | About 180°C fan |
| Is fan oven the same as gas mark? | No. Fan oven uses Celsius settings; gas mark is a numbered gas oven setting. |
| Is fan conversion exact? | No. It is a practical estimate and ovens vary. |
FAQs
What does fan oven mean?
A fan oven uses a fan to circulate hot air around the oven. This can cook food more evenly and often means a lower temperature is used than for a conventional oven.
How much lower should a fan oven be?
A common practical estimate is to reduce the conventional oven temperature by about 20°C. For example, 180°C conventional is often treated as about 160°C fan.
Is 180°C fan the same as 180°C conventional?
No. A fan oven circulates heat, so 180°C fan can cook more strongly than 180°C conventional. If a recipe says 180°C conventional, a fan estimate is usually about 160°C.
Should I change the cooking time for a fan oven?
Sometimes. Lowering the temperature is the usual first adjustment, but you should still check food near the end of the cooking time because ovens and recipes vary.