Celsius to Kelvin
One °C equals 274.15 K. Type any number and the answer appears as you type — the maths happens in your browser.
The same value in every unit
| Unit | Value |
|---|
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Common values
| Celsius | Kelvin |
|---|---|
| -40 °C | 233.15 K |
| -20 °C | 253.15 K |
| -10 °C | 263.15 K |
| 0 °C | 273.15 K |
| 10 °C | 283.15 K |
| 20 °C | 293.15 K |
| 25 °C | 298.15 K |
| 30 °C | 303.15 K |
| 37 °C | 310.15 K |
| 50 °C | 323.15 K |
| 100 °C | 373.15 K |
| 200 °C | 473.15 K |
How to use
- Enter the number of Celsius in the field.
- The result in Kelvin updates on every keystroke.
- Use the table below for the values people look up most often.
Formula and reverse conversion
The formula
To convert by hand: K = °C + 273.15. Going back the other way, one K is -272.15 °C.
Why you cannot just multiply
Celsius, Fahrenheit and Kelvin start counting from different points, so a temperature is converted with a formula rather than a factor. That is why −40 is the same number in Celsius and Fahrenheit, and why a difference between two temperatures converts differently from a temperature itself.
K = °C + 273.15
Frequently asked questions
How many Kelvin are in one Celsius?
One °C is 274.15 K.
How do I convert Celsius to Kelvin?
Multiply by the factor: K = °C + 273.15.
Is the result exact?
The factors are the exact legal definitions, and up to ten significant digits are kept in the answer. Rounding happens only in the display.
How do I convert Kelvin back to Celsius?
One K is -272.15 °C — or open the reverse page linked below.