How oven temperature conversion works
Fahrenheit and Celsius are linear scales with different starting points and step sizes, so converting is a subtract-and-multiply job. Gas marks, used on UK oven dials, are an older scale where each mark from 1 to 9 is 25 °F apart. The converter also shows the rounded figure a recipe would print, since nobody sets an oven to 176.7 °C.
The formula
°F = °C × 9 ÷ 5 + 32
gas mark n (1–10) = 250 + 25 × n °F · gas 1/2 = 250 °F · gas 1/4 = 225 °F
convection ≈ recipe temperature − 25 °F (about 14 °C)
Example: 350 °F
| Step | Result |
|---|---|
| Celsius: (350 − 32) × 5 ÷ 9 | 176.7 °C (shown as 177 °C) |
| Recipe-style rounding | 350 °F · 180 °C |
| Gas mark: (350 − 250) ÷ 25 | 4 |
| Convection: 350 − 25 | 325 °F · 163 °C |
Common oven temperatures
| °F | °C (recipe) | Gas mark | Description / typical use |
|---|---|---|---|
| 225 | 110 | 1/4 | Very low: meringues, drying |
| 250 | 120 | 1/2 | Very low: slow roasting |
| 275 | 140 | 1 | Low: braises, custards |
| 300 | 150 | 2 | Low: cheesecake |
| 325 | 160–170 | 3 | Moderately low: turkey, pound cake |
| 350 | 180 | 4 | Moderate: cakes, cookies, casseroles |
| 375 | 190 | 5 | Moderately hot: muffins, pies |
| 400 | 200 | 6 | Hot: roast vegetables, bread |
| 425 | 220 | 7 | Hot: crisping, puff pastry |
| 450 | 230 | 8 | Very hot: pizza, quick roasting |
| 475 | 240 | 9 | Very hot: artisan bread, pizza |
| 500 | 260 | 10 | Maximum on many ovens |
Tips
- Get an oven thermometer. Many ovens run 10 to 25 °F off their dial. A cheap thermometer tells you which way yours leans.
- Convection: lower the heat or the time. Drop 25 °F, or keep the temperature and start checking about a quarter of the way early.
- Preheat fully. Give the oven 15 to 20 minutes, longer with a baking stone, even after the beep.
- Watch for "fan" in UK recipes. A recipe that says 160 °C fan means about 180 °C in a conventional oven.
Frequently asked questions
What is 350 °F in Celsius?
350 °F is 176.7 °C. Recipes almost always round it to 180 °C, which is also gas mark 4. For a fan oven, use about 160 °C.
How do I convert Fahrenheit to Celsius?
Subtract 32, then multiply by 5/9. For 400 °F: (400 − 32) × 5 ÷ 9 = 204.4 °C, which recipes round to 200 °C. To go the other way, multiply Celsius by 9/5 and add 32.
How much lower should I set a convection oven?
The usual rule is 25 °F lower than the recipe says, or start checking for doneness earlier. UK recipes typically say about 20 °C lower for a fan oven. Many newer US ovens apply this reduction automatically in convection mode, so check your manual before subtracting twice.
What does gas mark mean?
Gas mark is the temperature scale printed on gas oven dials in the UK and Ireland. Gas mark 1 is 275 °F (140 °C), and each step above that adds 25 °F, up to gas mark 9 at 475 °F (240 °C). Gas marks 1/4 and 1/2 cover the very low temperatures used for meringues and slow cooking.
Why do recipes use 180 °C instead of 177 °C?
Home ovens swing by 10 to 25 degrees as they cycle on and off, and most dials are marked in steps of 10 °C or 25 °F. So recipe writers round: 350 °F becomes 180 °C, 375 °F becomes 190 °C, and 400 °F becomes 200 °C.
Rates and figures last checked October 2026.
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