The quick answer: gas mark 4 is 180°C, or 350°F, the moderate oven most baking uses. The gas mark converter turns any gas mark into Celsius, Fahrenheit and the fan-oven setting, or works backwards from a temperature, and the chart below covers every mark.
Gas mark conversion chart
| Gas mark | Celsius | Fahrenheit | Fan °C | Description |
|---|---|---|---|---|
| 1/4 | 110°C | 225°F | 90°C | Very cool |
| 1/2 | 120°C | 250°F | 100°C | Very cool |
| 1 | 140°C | 275°F | 120°C | Cool |
| 2 | 150°C | 300°F | 130°C | Cool |
| 3 | 160°C | 325°F | 140°C | Warm |
| 4 | 180°C | 350°F | 160°C | Moderate |
| 5 | 190°C | 375°F | 170°C | Moderately hot |
| 6 | 200°C | 400°F | 180°C | Hot |
| 7 | 220°C | 425°F | 200°C | Hot |
| 8 | 230°C | 450°F | 210°C | Very hot |
| 9 | 240°C | 475°F | 220°C | Very hot |
The Celsius figures match the values printed on oven dials, which is why gas mark 4 shows as 180°C even though the exact conversion of 350°F is 177°C.
How the gas mark scale works
Gas marks are the numbered settings on a gas oven, running from a quarter up to nine. The steps are even: from gas mark 1 upward, each mark is about 14°C hotter than the last. That makes the scale easy to reason about once you anchor one point. Gas mark 4 at 180°C is the baking workhorse, gas mark 6 at 200°C is for roasting, and gas mark 1 at 140°C suits slow cooking.
Converting a temperature to a gas mark
To go from Celsius or Fahrenheit to a gas mark, you round to the nearest mark, since a gas dial has no in-between settings. 180°C lands on gas mark 4, 200°C on gas mark 6, and 220°C on gas mark 7. Enter any temperature into the gas mark converter and it picks the closest mark for you and shows the degrees in both scales.
The fan-oven setting
A fan, or convection, oven moves hot air around the food, so it browns and cooks faster at the same setting. The common rule is to run a fan oven about 20°C below the conventional figure. So gas mark 4 at 180°C conventional becomes about 160°C in a fan oven. Recipes are written for conventional ovens unless they say otherwise, so lower the setting if yours has a fan and check the food a few minutes early.
Convert any setting
Enter a gas mark, or a temperature in any scale, into the gas mark converter and read the rest. For the wider view across Fahrenheit, Celsius and fan, see the oven temperature conversion chart. If you are moving a recipe to an air fryer, see how to convert an oven recipe to air fryer.
