The Celsius to Fahrenheit formula
Converting Celsius to Fahrenheit takes one short formula: °F = °C × 9/5 + 32. Multiply the Celsius temperature by nine fifths (that is, by 1.8), then add 32. The two scales put their zero points in different places, which is why you need the +32 shift: temperature is the one conversion you can never do with multiplication alone.
Worked example: take a mild 20 °C day. Multiply by 9/5 to get 36, add 32, and you have 68 °F. Going the other way, the reverse formula is °C = (°F − 32) × 5/9: subtract 32 first, then multiply by five ninths.
For a quick estimate in your head, use the shortcut "double it and add 30": 20 °C doubles to 40, plus 30 gives 70 °F, close to the true 68. It's only approximate, though, and drifts by a few degrees the further you move from about 10 °C (where it happens to be exact). Use it for weather chat, not for cooking or science.
Celsius to Fahrenheit chart
Exact values from the formula. Handy anchors include −40° (the one temperature where both scales agree), 0 °C = 32 °F (freezing), 37 °C = 98.6 °F (body temperature) and 100 °C = 212 °F (boiling).
| Celsius (°C) | Fahrenheit (°F) | Good to know |
|---|---|---|
| −40 °C | −40 °F | The scales cross (same number on both) |
| −20 °C | −4 °F | Deep-freezer territory |
| −10 °C | 14 °F | A hard frost |
| 0 °C | 32 °F | Water freezes |
| 5 °C | 41 °F | Fridge-cold morning |
| 10 °C | 50 °F | Cool day |
| 15 °C | 59 °F | Mild |
| 20 °C | 68 °F | Comfortable room temperature |
| 25 °C | 77 °F | Warm day |
| 30 °C | 86 °F | Hot day |
| 37 °C | 98.6 °F | Human body temperature |
| 40 °C | 104 °F | Heatwave |
| 50 °C | 122 °F | Hottest recorded air temperatures |
| 100 °C | 212 °F | Water boils (at sea level) |
| 180 °C | 356 °F | Moderate oven |
| 200 °C | 392 °F | Hot oven |
| 220 °C | 428 °F | Very hot oven |
Oven temperatures
Recipes round oven temperatures to friendly numbers, so the Fahrenheit you see in an American cookbook rarely matches the exact conversion. 180 °C is really 356 °F, but recipes say 350 °F, and at oven precision that difference doesn't matter. The table below gives both the exact conversion and the figure recipes commonly use, plus the UK gas mark.
| Oven description | °C | Exact °F | Common in recipes | Gas mark |
|---|---|---|---|---|
| Very slow | 120 °C | 248 °F | 250 °F | ½ |
| Slow | 150 °C | 302 °F | 300 °F | 2 |
| Moderate | 180 °C | 356 °F | 350 °F | 4 |
| Moderately hot | 190 °C | 374 °F | 375 °F | 5 |
| Hot | 200 °C | 392 °F | 400 °F | 6 |
| Very hot | 230 °C | 446 °F | 450 °F | 8 |
If you're using a fan-forced (convection) oven, the usual advice is to set it about 20 °C lower than the conventional temperature a recipe gives. Check your oven's manual.
Need more than temperature? The universal converter on our home page handles length, weight, volume, area, speed, pressure and more in one tool, and pairs nicely with the cups to grams converter when an American recipe throws both Fahrenheit ovens and cup measurements at you. For quick answers, try the FAQ.