Temperature conversion formulas
°F = °C × 9 ÷ 5 + 32 °C = (°F − 32) × 5 ÷ 9
K = °C + 273.15 °C = K − 273.15
°R = °F + 459.67 = K × 9 ÷ 5
Example: water boils at 100 °C, which is 100 × 9 ÷ 5 + 32 = 212 °F, or 373.15 K. Normal body temperature, 98.6 °F, is (98.6 − 32) × 5 ÷ 9 = 37 °C.
Quick estimate in your head: double the Celsius and add 30. 20 °C → about 70 °F (exactly 68). It's close for everyday weather and drifts off at extremes.
Temperature chart
| Celsius | Fahrenheit | What it is |
|---|---|---|
| -40 °C | -40 °F | Where Celsius and Fahrenheit are equal |
| -18 °C | -0.4 °F | Freezer (about 0 °F) |
| 0 °C | 32 °F | Water freezes |
| 4 °C | 39.2 °F | Fridge |
| 10 °C | 50 °F | Cool day |
| 20 °C | 68 °F | Room temperature |
| 25 °C | 77 °F | Warm day |
| 30 °C | 86 °F | Hot day |
| 37 °C | 98.6 °F | Body temperature |
| 38 °C | 100.4 °F | Fever |
| 40 °C | 104 °F | Heat wave |
| 100 °C | 212 °F | Water boils at sea level |
| 160 °C | 320 °F | Low oven (about 320 °F) |
| 180 °C | 356 °F | Moderate oven (356 °F, often rounded to 350) |
| 200 °C | 392 °F | Hot oven (392 °F, often rounded to 400) |
| 220 °C | 428 °F | Very hot oven (428 °F, often rounded to 425) |
For lengths, weights, volumes and more, use the unit converter.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply by 9, divide by 5 and add 32. 25 °C × 9 ÷ 5 = 45, plus 32 = 77 °F.
At what temperature are Celsius and Fahrenheit the same?
−40. −40 °C is exactly −40 °F.
What is 350 °F in Celsius?
About 177 °C. Recipes usually round it to 180 °C, or gas mark 4.
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