Oven temperatures · gas mark guide
100°C to gas mark
100°C is below gas mark ¼, the lowest setting on a gas oven and 212°F. Check if your recipe means a fan oven: if 100°C is the fan temperature, the conventional equivalent is 120°C, which is gas mark ½.
Chart checked against Delia Smith and Waitrose on .
Gas mark
Below ¼
nearest setting
Fahrenheit
212°F
exact conversion
Fan oven
80°C
if 100°C is conventional
If 100°C is fan
Gas ½
120°C conventional
Gas mark conversion chart
The row nearest to 100°C is gas mark ¼.
| Gas mark | Conventional | Fan | Fahrenheit | Heat |
|---|---|---|---|---|
| Gas ¼ | 110°C | 90°C | 225°F | Very cool |
| Gas ½ | 120°C | 100°C | 250°F | Very cool |
| Gas 1 | 140°C | 120°C | 275°F | Very low |
| Gas 2 | 150°C | 130°C | 300°F | Very low |
| Gas 3 | 170°C | 150°C | 325°F | Low |
| Gas 4 | 180°C | 160°C | 350°F | Moderate |
| Gas 5 | 190°C | 170°C | 375°F | Moderately hot |
| Gas 6 | 200°C | 180°C | 400°F | Hot |
| Gas 7 | 220°C | 200°C | 425°F | Hot |
| Gas 8 | 230°C | 210°C | 450°F | Very hot |
| Gas 9 | 240°C | 220°C | 475°F | Very hot |
Conventional or fan?
UK recipes often give two figures, such as 200°C or 180°C fan. If yours just says 100°C, it usually means a conventional oven, so a fan oven should be set to 80°C and a gas oven to below gas mark ¼, the lowest setting on a gas oven.
Exact conversion
100°C × 9 ÷ 5 + 32 = 212°F. The closest gas mark on the chart is gas mark ¼, which is 110°C and 225°F.
What cooks at 100°C
100°C is cooler than any gas mark. It is mostly used for drying meringues or keeping food warm; on a gas oven, use the lowest setting and prop the door open slightly if the recipe allows it.
Other temperatures
- 110°C to gas mark (gas ¼)
- 120°C to gas mark (gas ½)
- 130°C to gas mark (gas 1)
gas mark ¼ in full · Full gas mark conversion chart · Convert any temperature
Common questions
What gas mark is 100°C?
Below gas mark ¼, the lowest setting on a gas oven.
What is 100°C in a fan oven?
80°C, if the recipe's 100°C is for a conventional oven.
What gas mark is 100°C fan?
A fan setting of 100°C matches 120°C in a conventional oven, which is gas mark ½.
What is 100°C in Fahrenheit?
212°F exactly.
Sources and assumptions
- Conventional means an electric oven with the fan off. Fan settings are 20°C lower.
- Recipe charts round temperatures to the nearest 10°C or 25°F, so exact conversions differ by a few degrees.
- Delia Smith: oven temperatures and conversions (gas marks 1 to 9, fan ovens)
- Waitrose: conversion charts (gas marks ¼ and ½)
Ovens vary. An oven thermometer shows what yours is really doing.