To convert a gas mark to an air fryer setting, convert the gas mark to its conventional Celsius temperature, then subtract 15°C and reduce the time by 20%. Gas mark 6 is 200°C, which becomes 185°C in the air fryer.
Celsius, fan ovens and gas marks — the way British and Australian recipes are written
Gas Mark to Air Fryer Chart
| Gas mark | Conventional | Fan oven | Air fryer | °F (air fryer) |
|---|---|---|---|---|
| ¼ | 110°C | 90°C | 95°C | 200°F |
| ½ | 120°C | 100°C | 105°C | 220°F |
| 1 | 140°C | 120°C | 125°C | 255°F |
| 2 | 150°C | 130°C | 135°C | 275°F |
| 3 | 170°C | 150°C | 155°C | 310°F |
| 4 | 180°C | 160°C | 165°C | 330°F |
| 5 | 190°C | 170°C | 175°C | 350°F |
| 6 | 200°C | 180°C | 185°C | 365°F |
| 7 | 220°C | 200°C | 205°C | 400°F |
| 8 | 230°C | 210°C | 215°C | 420°F |
| 9 | 240°C | 220°C | 225°C | 435°F |
Time: multiply the recipe time by 0.8 in every case. A 40-minute bake at gas mark 6 becomes 32 minutes at 185°C.
Gas marks describe a conventional, still-air oven — gas ovens have no fan. That is why the conversion here takes the full 15°C reduction rather than the smaller 10°C used for fan ovens. An air fryer moves air aggressively across the food, and the reduction compensates for the resulting jump in surface heat transfer.
What is gas mark 4 in an air fryer?
165°C, or about 330°F, with the time reduced by 20%. Gas mark 4 is 180°C conventional, the standard general-purpose baking temperature in British recipes.
What is gas mark 6 in an air fryer?
185°C, or about 365°F. Gas mark 6 is 200°C conventional and the most common roasting temperature in UK recipes — chips, roast potatoes, chicken pieces.
Why do gas ovens need the larger reduction?
Because they have no fan at all. The 15°C reduction exists to compensate for adding forced air circulation. A fan oven already has it, so only 10°C remains; a gas oven has none, so the full correction applies.
Do gas ovens have hot spots?
Yes, more than electric ovens, which is part of why converted times are estimates on the first attempt. Gas ovens are typically hotter at the top and near the burner, and most British cooks unconsciously compensate by shelf position. An air fryer has a hot zone near the fan instead, which is why shaking or turning matters more.
How do I convert a gas mark recipe that gives no temperature?
Use the chart above to read across from the gas mark to the air fryer column. If the recipe gives a fan figure as well, use the fan oven conversion instead — it is the more reliable starting point because it needs a smaller adjustment.
Related conversions and adjacent topics
Fan ovens and conventional ovens take different reductions, because a fan figure has already been adjusted once. The fan oven conversion covers that distinction, which is the most common source of undercooked results in UK kitchens.
The UK oven to air fryer converter works in Celsius throughout and defaults to fan oven, so no cross-system rounding is involved.
Frequently asked questions
What is gas mark 5 in an air fryer?
175°C, about 350°F, with time reduced by 20%.
What is gas mark 7 in an air fryer?
205°C, about 400°F. This is the standard high-roast setting.
Is gas mark 4 the same as 180°C?
Yes, gas mark 4 is 180°C conventional, or 160°C fan.
Do American recipes use gas marks?
No. Gas marks are used in the UK and Ireland. American recipes give Fahrenheit, which converts directly — see the Fahrenheit chart.
Can I convert an air fryer recipe back to gas mark?
Add 15°C to the air fryer temperature to get the conventional figure, then read the gas mark from the chart. Multiply the time by 1.25.