To convert Fahrenheit to Celsius, subtract 32 and divide by 1.8: °C = (°F − 32) ÷ 1.8. To convert Celsius to Fahrenheit, multiply by 1.8 and add 32: °F = °C × 1.8 + 32. So 350°F works out to 176.7°C, which recipes round to 180°C, and water boils at 100°C (212°F).
Key facts
- NIST's exact formulas: °C = (°F − 32) ÷ 1.8 and °F = °C × 1.8 + 32.
- Water freezes at 0°C (32°F) and boils at about 100°C (212°F) at sea level.
- A change of 1°C equals a change of 1.8°F.
- Fan ovens run about 20°C lower than conventional settings (Which?); King Arthur Baking lowers convection baking by 25°F.
- Celsius and centigrade name the same scale; the international metrology committee chose "degree Celsius" in 1948.
What is the Fahrenheit to Celsius formula?
The Fahrenheit to Celsius formula is °C = (°F − 32) ÷ 1.8. NIST, the US measurement agency, gives it in exactly that form. Dividing by 1.8 is the same as multiplying by 5/9, so you'll also see it written °C = (°F − 32) × 5/9.
The two steps do two separate jobs. Subtracting 32 lines up the zero points, because water freezes at 32°F but 0°C. Dividing by 1.8 fixes the size of the degree: the gap from freezing to boiling is 180 Fahrenheit degrees but only 100 Celsius degrees, and 180 ÷ 100 = 1.8.
How to calculate Fahrenheit to Celsius: worked examples
- 350°F: 350 − 32 = 318; 318 ÷ 1.8 = 176.7°C. Recipes round this to 180°C. See 350°F to °C.
- 40°F: 40 − 32 = 8; 8 ÷ 1.8 = 4.4°C. This is the refrigerator limit, which FoodSafety.gov writes as 4°C.
- 165°F: 165 − 32 = 133; 133 ÷ 1.8 = 73.9°C, given as 74°C on federal charts. See 165°F to °C.
How to convert Celsius to Fahrenheit
To convert Celsius to Fahrenheit, multiply by 1.8 (or 9/5) and then add 32: °F = °C × 1.8 + 32. Do the multiplying first; adding 32 first gives a wrong answer.
- 180°C: 180 × 1.8 = 324; 324 + 32 = 356°F. US recipes call this 350°F. See 180°C to °F.
- 200°C: 200 × 1.8 = 360; 360 + 32 = 392°F, usually given as 400°F. See 200°C to °F.
- 220°C: 220 × 1.8 = 396; 396 + 32 = 428°F, usually given as 425°F. See 220°C to °F.
For any other number, our temperature converter does the math both ways.
Is there an easy way to convert Fahrenheit to Celsius?
Yes: subtract 30 and halve. It's quick, and it's close for everyday weather, but it drifts badly at oven temperatures. The shortcut swaps 32 for 30 and 1.8 for 2. Those two errors cancel at exactly 50°F (10°C either way), and the gap grows the farther you go from 50°F.
| °F | Exact °C | Shortcut: (°F − 30) ÷ 2 | Shortcut error |
|---|---|---|---|
| 32°F | 0°C | 1°C | 1° too high |
| 50°F | 10°C | 10°C | None |
| 68°F | 20°C | 19°C | 1° too low |
| 165°F | 73.9°C | 67.5°C | 6.4° too low |
| 212°F | 100°C | 91°C | 9° too low |
| 350°F | 176.7°C | 160°C | 16.7° too low |
| 450°F | 232.2°C | 210°C | 22.2° too low |
Use the shortcut to decide whether to grab a jacket, not to set an oven or check a roast. The reverse version, double the Celsius and add 30, has the same problem: 180°C comes out as 390°F instead of 356°F.
Oven temperature conversion chart
Recipes round oven temperatures to tidy numbers rather than using exact conversions. This chart shows the exact Celsius figure, the rounded setting used in recipes, the fan-oven setting and the UK gas mark. The rounded, fan and gas mark columns follow the conversion table published by the UK consumer group Which?.
| °F | Exact °C | Recipe °C | Fan oven °C | Gas mark |
|---|---|---|---|---|
| 275°F | 135.0 | 140 | 120 | 1 |
| 300°F | 148.9 | 150 | 130 | 2 |
| 325°F | 162.8 | 160 | 140 | 3 |
| 350°F | 176.7 | 180 | 160 | 4 |
| 375°F | 190.6 | 190 | 170 | 5 |
| 400°F | 204.4 | 200 | 180 | 6 |
| 425°F | 218.3 | 220 | 200 | 7 |
| 450°F | 232.2 | 230 | 210 | 8 |
| 475°F | 246.1 | 240 | 220 | 9 |
The rounding is a long-standing convention, not a conversion error. The exact column shows how far each familiar setting sits from a true conversion; the biggest gap here is 475°F, which is 246°C but listed as 240°C.
How much lower should a fan or convection oven be?
Which? says fan oven settings are typically about 20°C lower than conventional ones, which is why UK recipes often list two temperatures. In the US, King Arthur Baking's rule of thumb for convection baking is to lower the temperature by 25°F and start checking 10 minutes earlier than the recipe says. Some convection ovens make this adjustment automatically when you set a temperature, so check your manual before you subtract twice.
Key kitchen temperatures in Fahrenheit and Celsius
These are the reference points that come up most in cooking and food safety. The Celsius figures are the ones FoodSafety.gov publishes, rounded to whole degrees.
| What | °F | °C |
|---|---|---|
| Freezer | 0°F or below | −18°C or below |
| Water freezes | 32°F | 0°C |
| Refrigerator | 40°F or below | 4°C or below |
| Danger zone | 40–140°F | 4–60°C |
| Steaks, roasts, chops (+ 3-min rest) | 145°F | 63°C |
| Ground meat | 160°F | 71°C |
| Poultry and leftovers | 165°F | 74°C |
| Water boils (sea level) | 212°F | 100°C |
FoodSafety.gov's danger zone, 40°F to 140°F, is where bacteria grow fastest, which is why perishable food shouldn't sit out more than 2 hours, or 1 hour above 90°F (32°C). The full list of safe minimums is on our cooking temperatures page.
What is room temperature in Celsius?
NIST uses 20°C (68°F) as its example of room temperature. Real rooms vary by several degrees either way, so treat it as a reference point rather than a rule. For food safety, any ordinary room temperature sits inside the danger zone, so the same 2-hour limit applies; see how long food can sit out.
Celsius vs centigrade: is there a difference?
No. Centigrade is the older name for the same scale. In 1948 the International Committee for Weights and Measures (CIPM) considered three names, "degree centigrade," "centesimal degree" and "degree Celsius," and chose degree Celsius. A reading of 200 degrees centigrade is 200°C, or 392°F.
Degrees Celsius to kelvin
Kelvin is the scientific temperature scale. One kelvin is the same size as one degree Celsius, so converting only shifts the zero: K = °C + 273.15, per NIST. Room temperature, 20°C, is 293.15 K. Kitchens never need kelvin, but the formula is handy for homework.
Questions people ask
What is the easiest way to convert Fahrenheit to Celsius?
Subtract 30 and halve for a rough figure near everyday temperatures. For cooking, use the exact formula, (°F − 32) ÷ 1.8, or a converter.
What is 350 degrees Fahrenheit in Celsius?
176.7°C exactly. Recipes round it to 180°C, gas mark 4, or 160°C in a fan oven.
Is centigrade the same as Celsius?
Yes. They're two names for one scale; "degree Celsius" has been the official name since 1948.
What is 40°F in Celsius?
4.4°C. It's the top safe temperature for a refrigerator, written as 4°C by FoodSafety.gov.
Do convection ovens cook faster?
Usually. The fan moves hot air around the food, so Which? sets fan ovens about 20°C lower and King Arthur Baking lowers convection bakes by 25°F and checks 10 minutes early.
Sources
- NIST: SI units: temperature
- NIST: SP 811 Appendix B.9, conversion factors
- BIPM: CIPM 1948, name of the degree of temperature (degree Celsius)
- Which?: Oven temperature conversion, Celsius to Fahrenheit, gas mark and fan
- King Arthur Baking: The convection conundrum
- FoodSafety.gov: 4 steps to food safety
- FoodSafety.gov: Cook to a safe minimum internal temperature
