Kelvin to Celsius
Convert Kelvin (K) to Celsius (°C). °C = K − 273.15. Runs locally in your browser.
Kelvin to Celsius table
| Kelvin | Celsius |
|---|---|
| -40 K | -313.15 °C |
| 0 K | -273.15 °C |
| 10 K | -263.15 °C |
| 20 K | -253.15 °C |
| 25 K | -248.15 °C |
| 30 K | -243.15 °C |
| 37 K | -236.15 °C |
| 50 K | -223.15 °C |
| 100 K | -173.15 °C |
Where this conversion shows up
Kelvin readings come out of physics problems, space articles and — surprisingly often — lighting: the "2700K warm white" on a bulb box is a real temperature, the temperature a glowing ideal filament would be. Turning those numbers back into familiar Celsius is a straight subtraction.
Worked example
The cosmic microwave background is 2.725 K: 2.725 − 273.15 = −270.4 °C, three degrees above absolute zero. A 5778 K figure for the Sun's surface is 5505 °C.
Rounding and precision
Pure offset, no scaling — keep whatever precision the kelvin figure had. For big values like stellar temperatures the 273 barely matters (5778 K vs 5505 °C); near absolute zero it is the whole story.
FAQ
What is the formula to convert Kelvin to Celsius?
°C = K − 273.15. For example, 25 K = -248.15 °C.
Is Kelvin to Celsius done in my browser?
Yes — the conversion runs locally; nothing is uploaded.
What does the kelvin number on a light bulb mean?
Color temperature: the temperature at which an ideal black body glows that color. 2700 K looks warm orange-white, 4000 K neutral, 6500 K bluish daylight. The bulb itself is not that hot.
What is room temperature in kelvin?
About 293–298 K (20–25 °C). Standard laboratory temperature is usually taken as 298.15 K, exactly 25 °C.