Gas Mark to Celsius Converter
Convert gas mark oven temperatures to Celsius. Free UK gas mark to celsius oven temperature converter.
Formula
°C = (Gas Mark x 14) + 121
Common Conversions
How British Gas Marks Translate to °C
Older UK ovens use Gas Marks instead of degrees: Gas Mark 1 = 140 °C, Mark 2 = 150 °C, Mark 3 = 170 °C, Mark 4 = 180 °C, Mark 5 = 190 °C, Mark 6 = 200 °C, Mark 7 = 220 °C, Mark 8 = 230 °C, Mark 9 = 240 °C. Each mark step is roughly 10-25 °C. Modern UK ovens show °C primarily; gas marks are now the secondary scale.
Recipe conversion: a gas oven 'preheat to Mark 6' = 200 °C, equivalent to a 'moderate to hot' setting. Mark 4 = 180 °C is the most common baking temperature (cakes, biscuits). Mark 7 = 220 °C is for breads and quick-roast vegetables. Mark 1 = 140 °C is for slow-cooking, casseroles, low-and-slow roasts.
Gas Mark to Celsius (and Fahrenheit)
| Gas Mark | °C | °F |
|---|---|---|
| 1/4 | 110 °C | 225 °F |
| 1/2 | 130 °C | 250 °F |
| 1 | 140 °C | 275 °F |
| 2 | 150 °C | 300 °F |
| 3 | 170 °C | 325 °F |
| 4 | 180 °C | 350 °F |
| 5 | 190 °C | 375 °F |
| 6 | 200 °C | 400 °F |
| 7 | 220 °C | 425 °F |
| 8 | 230 °C | 450 °F |
| 9 | 240 °C | 475 °F |
Frequently Asked Questions
Why do gas ovens use Marks not °C?
Pre-electronic gas ovens couldn't easily display precise temperatures, so a numbered scale (1-9) was used. The Mark system was standardised by British Gas in the 1950s. Modern gas ovens show °C; Mark labels persist for older recipes and oven dials.
Should I reduce temperature for fan/convection ovens?
Yes - reduce by 20 °C from the recipe's stated temperature. A recipe specifying 200 °C should be set to 180 °C in a fan oven. Same temperature transfer to food, less browning. The Mark equivalent is roughly one mark down (Mark 6 → Mark 5).
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