Temperature converter: °C, °F and K
Convert a temperature between Celsius, Fahrenheit and Kelvin. The calculator rejects values below absolute zero; Kelvin is written without a degree sign.
Enter a temperature to see the conversion.
Examples
- 0 °C = 32 °F = 273.15 K.
- 100 °C = 212 °F = 373.15 K.
- −40 °C = −40 °F.
The conversion formulas
Convert through Kelvin: K = (°F + 459.67) × 5/9 for Fahrenheit input, or K = °C + 273.15 for Celsius input. To return, °C = K − 273.15 and °F = (K − 273.15) × 9/5 + 32. Absolute zero is 0 K, equal to −273.15 °C and −459.67 °F.
Read the scale correctly
- Celsius is common in everyday use in most countries; Fahrenheit is still used in everyday settings in a few countries, including the United States.
- Kelvin is an absolute thermodynamic scale and is written K, without a degree sign.
- The converter changes temperature values; it does not calculate heat, thermal sensation or weather forecasts.
Frequently asked questions
What is the formula from Celsius to Fahrenheit?
°F = °C × 9/5 + 32. For the reverse conversion, °C = (°F − 32) × 5/9.
Why is Kelvin written without a degree sign?
Kelvin is the SI unit of thermodynamic temperature and uses the symbol K, not °K.
Can a temperature be below absolute zero?
This calculator accepts ordinary thermodynamic temperatures at or above 0 K, which corresponds to −273.15 °C.