Celsius to Fahrenheit converter
Type a temperature in degrees Celsius and see at once how many degrees Fahrenheit that is. You can also convert the other way, from Fahrenheit to Celsius. Kelvin is shown as well.
In degrees, with or without a minus. A sum works too, such as 98.6 or 100/2.
Fill in the fields; the answer appears here straight away.
How it's worked out
How it works
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Enter the values
Type the numbers or the formula. Decimals may use a point or a comma. No idea? Click Fill in an example.
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Instant answer
The answer appears as you type, with the most important intermediate values.
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See the working
Under "How it's worked out" you see the steps, handy for checking your own calculation.
The formula
- Celsius to Fahrenheit: °F = °C × 9 ÷ 5 + 32
- Fahrenheit to Celsius: °C = (°F − 32) × 5 ÷ 9
So 21 °C is 21 × 9 ÷ 5 + 32 = 69.8 °F. Water freezes at 0 °C (32 °F) and boils at 100 °C (212 °F). At −40 it is equally cold on both scales.
Conversion table
| °C | °F |
|---|---|
| -40 °C | -40 °F |
| -10 °C | 14 °F |
| 0 °C | 32 °F |
| 10 °C | 50 °F |
| 20 °C | 68 °F |
| 21 °C | 69.8 °F |
| 25 °C | 77 °F |
| 30 °C | 86 °F |
| 37 °C | 98.6 °F |
| 100 °C | 212 °F |
A rule of thumb for on the go
Double the degrees Celsius and add 30: 20 °C is roughly 70 °F (exactly 68). This works best between 0 and 30 °C. Fahrenheit is mostly used in the United States; nearly everywhere else uses Celsius.
Oven temperatures
| Celsius | Fahrenheit | Often written as |
|---|---|---|
| 150 °C | 302 °F | 300 °F |
| 180 °C | 356 °F | 350 °F |
| 200 °C | 392 °F | 400 °F |
| 220 °C | 428 °F | 425 °F |
American recipes round to the nearest 25 °F, so the exact conversion is a few degrees lower than the printed number. For baking this rarely matters, but you can enter the exact value if you want to be precise.
Weather and the body
Heat waves at 35 °C are 95 °F, and a freezing winter day of −10 °C is 14 °F. A room at 21 °C, the example above, is 69.8 °F. To check a speed in the same trip, use the km/h to mph converter.
Kelvin
Kelvin has the same step size as Celsius but starts at absolute zero: K = °C + 273.15. Scientists use it, as in the colour temperature of a lamp or the temperature of a gas in the physical constants formulas.
Frequently asked questions
Why do −40 °C and −40 °F match?
Set °C = °F in the formula and solve: x = x × 9 ÷ 5 + 32 gives x = −40. It is the one temperature where both scales agree.
How do I convert a temperature difference?
Multiply by 9 ÷ 5 only, without adding 32. A rise of 10 °C is a rise of 18 °F. The 32 only shifts the zero point, which does not matter for differences.
What is absolute zero in Celsius and Fahrenheit?
−273.15 °C, which is 0 K and −459.67 °F. The calculator also shows the Kelvin value of every temperature you enter.
What is normal body temperature in Fahrenheit?
37 °C is 98.6 °F. A fever of 38.5 °C is 101.3 °F, and 40 °C is 104 °F.