Kelvin to Celsius Converter (K to °C)

How to convert kelvin to Celsius

Subtract 273.15:

°C = K − 273.15

300 K − 273.15 = 26.85 °C. The offset is exact: the Celsius scale is defined as the kelvin scale shifted by 273.15. A kelvin and a degree Celsius are the same size, so there is nothing to multiply. The result shows the subtraction worked out with your number and the temperature in Fahrenheit. To go the other way, use Celsius to kelvin.

Kelvin to Celsius chart

Kelvins (K)	Degrees Celsius (°C)
0 K	-273.15 °C
4.2 K	-268.95 °C
20 K	-253.15 °C
77 K	-196.15 °C
100 K	-173.15 °C
200 K	-73.15 °C
250 K	-23.15 °C
263.15 K	-10 °C
273.15 K	0 °C
283.15 K	10 °C
293.15 K	20 °C
298.15 K	25 °C
300 K	26.85 °C
310.15 K	37 °C
373.15 K	100 °C
500 K	226.85 °C
1,000 K	726.85 °C

Temperatures given in kelvin

What	Kelvin	Celsius	Fahrenheit
Absolute zero	0 K	−273.15 °C	−459.67 °F
Cosmic background radiation	2.725 K	−270.42 °C	−454.77 °F
Liquid helium boils	4.2 K	−268.95 °C	−452.1 °F
Liquid nitrogen boils	77.36 K	−195.79 °C	−320.4 °F
Water freezes	273.15 K	0 °C	32 °F
Room temperature (lab)	298.15 K	25 °C	77 °F
Human body	310.15 K	37 °C	98.6 °F
Water boils (sea level)	373.15 K	100 °C	212 °F

Physics and chemistry use kelvin because many laws — the ideal gas law, radiation from hot objects — need a scale that starts at zero. Problems written in kelvin are often answered in Celsius for a reader, so the conversion is the last step.

273 or 273.15?

For classwork and quick checks, subtracting 273 is accurate to 0.15 degree, well inside the precision of most thermometers. Use 273.15 when the kelvin value has decimals or when the answer feeds a further calculation, so rounding does not stack up.

Light bulbs and color temperature

Bulbs and camera settings list a color temperature in kelvin: 2,700 K is warm white, 5,000 K is daylight. The number is the temperature of an ideal glowing object of that color, not the heat of the bulb, so converting 2,700 K to 2,426.85 °C is correct arithmetic but says nothing about how hot an LED gets.

Kelvin in weather and climate data

Satellite and climate datasets often store air and sea-surface temperatures in kelvin so that values are never negative. A reading of 288 K is 14.85 °C, close to the global mean surface temperature, and 255 K — what Earth would average without its greenhouse effect — is −18.15 °C. Temperature differences, such as warming of 1.2 K since pre-industrial times, are the same number in degrees Celsius, because the two scales have the same step size; only absolute readings need the 273.15 subtraction.

Kelvin, Celsius and Fahrenheit

To go from Celsius to Fahrenheit, see Celsius to Fahrenheit; for the reverse, Fahrenheit to Celsius. Kelvin is written without a degree sign — 300 K, not 300 °K — a rule set in 1967.

Frequently asked questions

How do you convert kelvin to Celsius?

Subtract 273.15: °C = K − 273.15.

What is 300 K in Celsius?

26.85 °C — a warm room, about 80 °F.

What is 0 K in Celsius?

−273.15 °C, absolute zero; nothing can be colder.

What is 373.15 K in Celsius?

100 °C, the boiling point of water at sea level.

Is a kelvin the same size as a degree Celsius?

Yes. A change of 1 K equals a change of 1 °C; only the zero point differs.

Can a temperature in kelvin be negative?

No. The kelvin scale starts at absolute zero, so every real temperature is above 0 K.