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.
Frequently asked questions
Is the celsius to Fahrenheit free?
Yes. The celsius to Fahrenheit is completely free, with no account, sign-up or usage limit.
How accurate is the result?
The tool calculates with your browser's number precision. For important calculations, always double-check what you entered.
Does it work on my phone?
Yes. The tool works in any modern browser on a phone, tablet or computer.