How this calculator works
Kelvin and Celsius use the same size of degree, so the conversion is a single shift of the zero point. Absolute zero is 0 K or -273.15 °C. Celsius is the everyday scale in most countries, while kelvin is the SI base unit used in science and engineering. The page accepts either direction: pick kelvin as the source for a measurement on the scientific scale, or switch the two lists to go the other way.
Formula
°C = K - 273.15. K = °C + 273.15. The offset is an exact definition, so no rounding enters the conversion itself.
Worked example
300 K to Celsius: 300 - 273.15 = 26.85 °C. 273.15 K is 0 °C, the freezing point of water at standard pressure. 373.15 K is 100 °C. Absolute zero, 0 K, is -273.15 °C.
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Frequently asked questions
Why is 0 K equal to -273.15 °C?
The two scales share the same degree size but place zero differently. Kelvin starts at absolute zero, the coldest possible temperature, while Celsius places zero at the freezing point of water. The distance between the two zeros is 273.15 degrees.
Is kelvin written with a degree sign?
No. The kelvin is an SI base unit and its symbol is K, without a degree sign. Degrees Celsius keep the °C symbol.
Can a temperature be below 0 K?
No. Zero kelvin is absolute zero, so this page rejects any value below it, and below -273.15 °C when Celsius is the source.
Why does 293.15 K appear so often?
293.15 K is 20 °C, a common room temperature. Laboratories also quote 298.15 K, which is 25 °C.