0 °C in Fahrenheit
The freezing point of water on the Celsius scale.
- 0 × 9 ÷ 5 = 0
- 0 + 32 = 32
- Result: 32 °F
Water freezes at 32 °F, which is 273.15 K.
Temperature Converter
This converter switches between the three common temperature scales. Unlike length or weight, temperature scales have different zero points, so the conversion uses formulas rather than a single multiplier. Negative values are valid above absolute zero.
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Result
33.8 °F
Enter a value to convert The converted result appears here as you type.
Other common conversions +
How to use this tool
- 1 Enter a temperature and choose the scale you are converting from.
- 2 Choose Celsius, Fahrenheit or Kelvin as the target.
- 3 Press swap to reverse the direction and check the other two scales below the result.
- 4 Set the decimal places. Values below absolute zero are rejected with an explanation.
Formula and calculation logic
Celsius and Fahrenheit
°F = °C × 9 ÷ 5 + 32; °C = (°F − 32) × 5 ÷ 9
The two scales have different zero points and different step sizes. 0 °C is 32 °F, and a change of 1 °C equals a change of 1.8 °F.
Kelvin
K = °C + 273.15; °C = K − 273.15
Kelvin uses the same step size as Celsius but starts at absolute zero. 0 K is −273.15 °C, and Kelvin values are never negative.
Worked example
100 °F in Celsius
A warm day reported in Fahrenheit.
- 100 − 32 = 68
- 68 × 5 ÷ 9 = 37.7777…
- Displayed with 4 decimals: 37.7778 °C
100 °F is about 37.78 °C, slightly above normal body temperature.
Edge cases and accuracy
Absolute zero
Nothing can be colder than 0 K (−273.15 °C or −459.67 °F). The converter rejects values below absolute zero rather than returning an impossible temperature.
Kelvin has no degree symbol
Kelvin is written as K, not °K. The converter uses the correct symbol in results and unit labels.
Display rounding
Conversions between Fahrenheit and Celsius often produce repeating decimals. The displayed value is rounded, while the internal result keeps more precision.
Frequently asked questions
How do I convert Celsius to Fahrenheit? + −
Multiply by 9, divide by 5, then add 32. For example, 20 °C becomes 20 × 9 ÷ 5 + 32 = 68 °F.
Can temperatures be negative? + −
Yes, as long as they are above absolute zero. −40 °C is −40 °F, and −10 °C is 14 °F. Only values below 0 K are rejected.
Why is Kelvin used? + −
Kelvin starts at absolute zero, which makes it convenient in science. Its step size matches Celsius, so a change of 1 K equals a change of 1 °C.
What is absolute zero in Fahrenheit? + −
Absolute zero is 0 K, −273.15 °C or −459.67 °F.
Why does the result have so many decimals? + −
Fahrenheit–Celsius conversions often produce repeating decimals, such as 37.7777… for 100 °F. Reduce the decimal places to round the display.