How this oven temperature converter works
Oven dials around the world use three different scales. The United States uses degrees Fahrenheit, most of the rest of the world uses degrees Celsius, and many older British recipes use the Gas Mark scale. This tool converts between all three, then adds the two adjustments home cooks most often need: a fan (convection) setting and an air-fryer suggestion.
The maths is simple. To go from Fahrenheit to Celsius the tool uses C = (F − 32) × 5/9, and to go the other way F = C × 9/5 + 32. Gas Mark numbers don't follow a formula, so they are mapped to their standard temperatures — Gas Mark 4 is 350°F / 175°C, and each step up adds about 25°F.
Reference note: Celsius and Gas Mark values are rounded to the conventional figures printed on oven dials, so they may differ by a degree or two from the exact arithmetic. Fan and air-fryer settings are starting points — every appliance runs slightly differently, so check your food early.
Common oven temperatures at a glance
| Fahrenheit | Celsius | Gas Mark | Description |
|---|---|---|---|
| 225°F | 110°C | ¼ | Very cool / slow |
| 250°F | 120°C | ½ | Very cool |
| 275°F | 140°C | 1 | Cool |
| 300°F | 150°C | 2 | Cool |
| 325°F | 160°C | 3 | Warm |
| 350°F | 175°C | 4 | Moderate |
| 375°F | 190°C | 5 | Moderately hot |
| 400°F | 200°C | 6 | Moderately hot |
| 425°F | 220°C | 7 | Hot |
| 450°F | 230°C | 8 | Hot |
| 475°F | 240°C | 9 | Very hot |
Frequently asked questions
- What is 350°F in Celsius?
- 350°F is 175°C, using C = (F − 32) × 5/9. In recipes this is a moderate oven, equivalent to Gas Mark 4 — the most common baking temperature.
- What is Gas Mark 4?
- Gas Mark 4 is a moderate oven of about 350°F or 180°C. The gas mark scale rises in roughly 25°F steps, with Gas Mark 4 sitting in the middle as the everyday baking setting.
- How do I convert a conventional oven recipe to a fan oven?
- Set the temperature about 25°F (20°C) lower than the conventional recipe and watch the food, since fan ovens can also cook a little faster. So 350°F conventional becomes about 325°F fan.
- How do I convert oven temp to an air fryer?
- An air fryer is like a small, fast fan oven. Lower the recipe temperature by about 25°F and cut the cooking time by roughly 20%, then check early. So 400°F in the oven becomes about 375°F in the air fryer.
- What is 400°F in Celsius and Gas Mark?
- 400°F is 200°C and Gas Mark 6 — a moderately hot oven good for roasting and baking. The exact arithmetic gives about 204°C, rounded to the 200°C printed on dials.
- Why lower the temperature for a fan oven?
- A fan circulates hot air around the food, transferring heat more efficiently than the still air of a conventional oven. Lowering the set temperature by about 25°F (20°C) gives the same result.