How to convert Kelvin to Celsius
°C = K − 273.15
Apply the operations in the order shown. This formula converts a Kelvin temperature reading to Celsius, not a temperature difference. The source reading must be at least 0 K, the absolute-zero limit.
Worked examples
273.15 K ≈ 0 °C
273.15 − 273.15 ≈ 0
Water’s familiar freezing reference near standard atmospheric pressure.
373.15 K ≈ 100 °C
373.15 − 273.15 ≈ 100
Water’s familiar boiling reference near standard atmospheric pressure; actual boiling temperature changes with pressure.
Frequently asked questions
Can I use K to °C for a temperature difference?
For an interval, use only the degree-size ratio and omit any offset. This calculator converts scale readings. Kelvin and Rankine start at absolute zero; Celsius and Fahrenheit have different zero points.