QUICK ANSWER
Lower the temperature by 20°C when a recipe gives a conventional oven temperature and you have a fan oven: 180°C becomes 160°C fan, 200°C becomes 180°C fan and 220°C becomes 200°C fan. In Fahrenheit, lower a convection oven by about 25°F. If a UK recipe already says “fan”, use its number as written.
Convert to a fan temperature.
Conventional to fan oven chart.
| Conventional °C | Fan °C | °F (conventional) | Gas mark |
|---|---|---|---|
| 140°C | 120°C | 275°F | Gas 1 |
| 150°C | 130°C | 300°F | Gas 2 |
| 160°C | 140°C | 325°F | Gas 3 |
| 170°C | 150°C | 350°F | — |
| 180°C | 160°C | 350°F | Gas 4 |
| 190°C | 170°C | 375°F | Gas 5 |
| 200°C | 180°C | 400°F | Gas 6 |
| 210°C | 190°C | 400°F | — |
| 220°C | 200°C | 425°F | Gas 7 |
| 230°C | 210°C | 450°F | Gas 8 |
| 240°C | 220°C | 475°F | — |
| 250°C | 230°C | 475°F | Gas 9 |
Convection ovens in Fahrenheit.
US recipes give a conventional temperature in °F. For a convection (fan) setting, lower it by about 25°F: 350°F becomes 325°F, 400°F becomes 375°F and 425°F becomes 400°F. Many newer ovens with a convection setting make this adjustment automatically; check your oven’s manual before lowering it twice.
450°F is the temperature our recipe directions call for most often (192 recipes); in a fan oven that is 210°C fan or 425°F convection.
Cooking in a fan oven.
- Check early. Even at the lower temperature, start checking 5 to 10 minutes before the recipe says.
- Give food space. The fan needs room to move air; a crowded sheet pan steams instead of browning.
- Baking. Cakes and bread are the most sensitive to the 20°C drop; roast vegetables and sheet pan dinners are forgiving.
Common questions.
How do I convert a conventional oven temperature to fan?
Take 20°C off: 180°C conventional is 160°C fan. In Fahrenheit, take about 25°F off for a convection oven.
What is 180°C conventional in a fan oven?
160°C fan. It is gas mark 4, 350°F conventional.
What is 200°C conventional in a fan oven?
180°C fan. It is gas mark 6, 400°F conventional.
What is 220°C conventional in a fan oven?
200°C fan. It is gas mark 7, 425°F conventional.
Is 180°C fan the same as 200°C conventional?
Yes, near enough. A fan oven at 180°C cooks like a conventional oven at about 200°C.
Do I lower the temperature if the recipe already says fan?
No. If the recipe gives a fan temperature, use it as written.
Dinner planned before the oven goes on.
MealPot plans the week and writes one grocery list, so all that is left is the cooking.
The fan rule is the usual 20°C (about 25°F) reduction for fan and convection ovens. °F is converted from °C and rounded to the nearest 25°F; gas marks follow the UK scale. Recipe counts come from the directions in our recipe library, counted on 28 October 2026.
More kitchen references: tablespoons to cups · ounces in a cup · cups to grams · oven temperatures · gas marks · fan oven · butter · ingredient substitutes · kitchen essentials