Kelvin to Celsius Converter
Convert Kelvin to Celsius instantly. Enter a temperature in K to get °C by subtracting 273.15, with the reverse Celsius to Kelvin direction shown.
Updated 2026-06-14 · Free · No sign-up · Runs privately in your browser
Show the formula & steps
How the Kelvin to Celsius Converter Works
This tool converts Kelvin (K) to degrees Celsius (°C) and back. Kelvin is the SI base unit of temperature used in science, while Celsius is the everyday metric scale. They share the same degree size but have different zero points.
The Formula
Celsius = Kelvin − 273.15 Kelvin = Celsius + 273.15
A change of one kelvin equals a change of one degree Celsius, so the conversion is just a shift of 273.15.
Worked Example
Convert 300 K (a warm room) to Celsius:
- Celsius = 300 − 273.15 = 26.85 °C
The freezing point of water, 273.15 K:
- 273.15 − 273.15 = 0 °C
Going the other way, 37 °C in Kelvin:
- Kelvin = 37 + 273.15 = 310.15 K
Kelvin to Celsius Quick Reference
| Kelvin (K) | Celsius (°C) |
|---|---|
| 0 | -273.15 |
| 273.15 | 0 |
| 298.15 | 25 |
| 310.15 | 37 |
| 373.15 | 100 |
When to Use Each Scale
Scientists work in Kelvin because it begins at absolute zero, making it the correct unit for gas laws, thermodynamics and astrophysics where temperatures must be measured from the true zero of thermal energy. Celsius is friendlier for weather, cooking and body temperature. Converting Kelvin results back to Celsius makes lab and physics figures easier to interpret in everyday terms.
Frequently asked questions
How do I convert Kelvin to Celsius?+
Subtract 273.15 from the Kelvin temperature. For example, 300 K − 273.15 = 26.85 °C. To reverse it, add 273.15 to the Celsius value.
What is 273.15 K in Celsius?+
273.15 K equals 0 °C, the freezing point of water. The Kelvin scale starts at absolute zero, which is 273.15 degrees below the Celsius zero point.
Why do you subtract exactly 273.15?+
Kelvin and Celsius use the same degree size, but Kelvin starts at absolute zero rather than water's freezing point. Since absolute zero is 273.15 degrees below 0 °C, subtracting 273.15 converts Kelvin to Celsius.
What is 300 K in Celsius?+
300 K equals about 26.85 °C, a comfortable room temperature. Subtracting 273.15 from 300 gives 26.85.
Can the result be negative?+
Yes. Any Kelvin value below 273.15 K converts to a negative Celsius temperature. For example, 250 K is -23.15 °C. Kelvin itself, however, cannot be negative.