Kelvin to Celsius Converter

Convert kelvin to Celsius instantly, with a reference table covering cryogenics, light colour temperature and stellar surfaces.

Kelvins

Degrees Celsius

1 K = -272.15 °C

Multiply kelvins by 1, then add -273.15, to get degrees Celsius.

The link carries the values you entered, so whoever opens it sees the same result. Nothing is stored on our side — the numbers travel in the link itself.

Kelvins to degrees Celsius reference table

The conversions people look up most often, rounded to 2 decimal places.

Common kelvins to degrees Celsius conversions
Kelvin (K)	Degree Celsius (°C)
0 K	-273.15 °C
77 K	-196.15 °C
100 K	-173.15 °C
200 K	-73.15 °C
273.15 K	0 °C
293 K	19.85 °C
300 K	26.85 °C
310 K	36.85 °C
373.15 K	100 °C
1,000 K	726.85 °C
2,700 K	2,426.85 °C
5,000 K	4,726.85 °C
6,500 K	6,226.85 °C

The kelvins people look up most

273.15 K = 0 °C: Where water freezes, and the point the Celsius scale was built around. The 273.15 offset is a definition, so this conversion is never approximate.
300 K = 26.85 °C: Physicists use 300 K as a stand-in for room temperature because the arithmetic is easier.
1,100 K = 826.85 °C: Roughly a wood fire at its hottest, and the low end of the range a pottery kiln works in.
2,700 K = 2,426.85 °C: Not a temperature. On a light bulb, 2700 K describes the colour of the light: warm and yellowish, like an old incandescent.
4,000 K = 3,726.85 °C: Also a lighting specification rather than a temperature. 4000 K is neutral white, and converting it to 3,727 degrees is correct but meaningless.
5,778 K = 5,504.85 °C: The surface of the Sun, about 5,505 degrees. This one is a real temperature - and it is where the lighting scale borrowed its numbers from.

How the kelvin to celsius calculation works

The degrees are the same size, so:

°C = K − 273.15

Most people arrive here from one of two places, and they are almost unrelated.

Light bulbs. A bulb's "colour temperature" in kelvin is not how hot it gets — it is the temperature a theoretical black body would need to be to glow that colour. A 2700 K warm white bulb is not 2,426°C; it is a bulb whose light matches what an object at that temperature would emit. Converting it to Celsius is meaningless in practice, though the arithmetic still works:

2700 K — warm white, the incandescent look
4000 K — neutral white
5000 K — daylight
6500 K — cool daylight, the standard for colour-matching

Confusingly, higher kelvin looks "cooler" to the eye, because blue light comes from hotter sources than orange light.

Cryogenics and physics, where the conversion is real:

0 K → −273.15°C — absolute zero
4.2 K → −268.95°C — liquid helium, the coolant for superconducting magnets in MRI scanners
77 K → −196.15°C — liquid nitrogen
195 K → −78.15°C — dry ice sublimation
273.15 K → 0°C — water freezes
5772 K → 5,498.85°C — the Sun's surface

Write it as "77 K", not "77°K". The degree symbol was dropped in 1967; kelvin is an absolute unit and takes no degrees.

To convert back, add 273.15.

Frequently asked questions

What is the difference between colour temperature and CRI?

They describe different properties of the same lamp. Colour temperature in kelvin says what colour the light is - warm, neutral or blue. The colour rendering index says how faithfully that light shows the colours of what it falls on, on a scale where daylight scores 100. Two 4000 K bulbs with a CRI of 80 and 95 look markedly different on skin and fabric, and the kelvin figure will not tell you which is which.

Why are the hottest stars blue and the coolest red?

Because colour follows temperature, and our vocabulary runs the other way. A red star sits around 3,600 K, which is 3,327°C, while a blue one can exceed 12,000 K, or 11,727°C - so the colours we call warm belong to the cooler objects. Stellar classes run O, B, A, F, G, K, M from hottest to coolest, which is the same inversion lighting catalogues inherited.

Why do weather models store temperature in kelvin?

Because atmospheric physics works in ratios. Pressure, density and temperature are tied together by the gas law, which only holds on an absolute scale, so soundings and model output are kept in kelvin and converted to Celsius for the forecast. A 10 K warming at 250 K is a 4% change in absolute temperature; the same ten degrees written as −23°C to −13°C has no meaningful percentage at all.

Kelvin to Celsius Converter