Gas Mark to Celsius Converter – Oven Temperature Chart in 3 Easy Steps

Use this free gas mark to Celsius converter to turn UK oven settings into °C, or type a Celsius temperature to find the matching gas mark. It shows the Fahrenheit step too, plus a full oven temperature chart for baking and roasting.

Older British cookbooks, many family recipes and plenty of UK and Irish gas cookers still use gas marks. Electric ovens and most modern recipes use Celsius or Fahrenheit. Get it wrong and a cake that should be gently baked comes out burnt or raw in the middle.

This gas mark to Celsius converter works both ways, updates as you type and keeps a printed-style chart on screen for quick checks.

What Is a Gas Mark?

Gas mark is an oven temperature scale used on gas cookers in the United Kingdom, Ireland and some Commonwealth countries. It runs from gas mark ¼ (very cool) to gas mark 9 or 10 (very hot). Each whole step above gas mark 1 adds 25°F, which is roughly 14°C.

Gas Mark to Celsius Formula

• Gas mark 1 and above: °F = (gas mark × 25) + 250
• Gas mark ½: 250°F, and gas mark ¼: 225°F
• Fahrenheit to Celsius: °C = (°F − 32) × 5 ÷ 9
• Celsius to gas mark (from 135°C up): gas mark = ((°C × 9 ÷ 5) + 32 − 250) ÷ 25

Recipe charts round the results to the nearest 10°C, which is why gas mark 4 is usually listed as 180°C even though the exact figure is 176.7°C. Ovens vary by more than that, so the rounded numbers are fine for cooking.

Gas Mark Conversion Chart

How to Use the Gas Mark to Celsius Converter

Step 1: Enter the Gas Mark

Type the gas mark from your recipe in the Gas Mark box. Gas mark 6 converts to 204.4°C, and the formula panel shows the 400°F step in between. Use Copy °C to copy the result.

Step 2: Convert Celsius Back to Gas Mark

Type in the Celsius box instead to go the other way. 220°C works out to gas mark 7.1, so set your gas oven to 7.

Step 3: Check the Oven Temperature Chart

The chart under the converter lists every gas mark with its usual Celsius and Fahrenheit setting, so you can find a match at a glance while you cook.

Fan Ovens and Gas Marks

Fan (convection) ovens cook faster because hot air circulates. If your recipe gives a gas mark and you use a fan oven, convert to Celsius and then lower it by about 20°C. Gas mark 4 becomes about 160°C fan instead of 180°C.

Common Recipe Temperatures

• Meringues and slow-dried fruit: gas mark ¼ to ½ (110 to 130°C)
• Rich fruit cake: gas mark 2 to 3 (150 to 170°C)
• Sponge cakes and cookies: gas mark 4 (180°C)
• Roast chicken: gas mark 5 to 6 (190 to 200°C)
• Bread and roast potatoes: gas mark 6 to 7 (200 to 220°C)
• Pizza and puff pastry: gas mark 8 to 9 (230 to 240°C)

Converting other recipe units? Try the Grains to Grams Converter for small weights, or the Volumetric Flow Rate Converter for kitchen extractor fans.

Frequently Asked Questions