Celsius to Kelvin
Result:
Enter a temperature to convert.
Convert Celsius to kelvin. From is set to Celsius and To is set to kelvin. The result updates as you type. A temperature interval of 1 °C is an interval of 1 K, and 0 °C is 273.15 K. Other units are on the temperature converter. The other direction is kelvin to Celsius.
Celsius to kelvin formula
NIST Special Publication 330, Section 2 defines Celsius temperature from thermodynamic temperature by t/°C = T/K − 273.15. The degree Celsius is the same size as the kelvin.
Formula: K = °C + 273.15.
The converter adds 273.15, then rounds the displayed result to two decimal places.
Example: 0 °C + 273.15 = 273.15 K. The converter shows 273.15 K. 20 °C shows 293.15 K.
Celsius to kelvin reference table
Each value below is the converter result at two decimal places. Enter the same Celsius temperature in the form above and the result should match.
| Celsius (°C) | Kelvin (K) |
|---|---|
| −273.15 | 0.00 |
| −40 | 233.15 |
| −20 | 253.15 |
| 0 | 273.15 |
| 20 | 293.15 |
| 25 | 298.15 |
| 37 | 310.15 |
| 100 | 373.15 |
| 180 | 453.15 |
| 200 | 473.15 |
Celsius to kelvin examples
Freezing: 0 °C is 273.15 K. Absolute zero, −273.15 °C, shows 0.00 K.
Room and body: 20 °C is 293.15 K, and 37 °C is 310.15 K.
Boiling figure and an oven: 100 °C is 373.15 K. That arithmetic is exact. It does not mean water boils at 100 °C at every pressure. An oven set to 180 °C is 453.15 K.
Quick mental math (approximation)
To estimate kelvin, add 273 to the Celsius temperature. Example: 20 °C + 273 is about 293 K. The exact result is 293.15 K.
This shortcut is an approximation. It is always 0.15 kelvin low. That is close enough for a rough sense of room temperature and too coarse for a lab note. Use the converter or the exact formula when the 273.15 offset matters.
Celsius to kelvin FAQ
How do I convert Celsius to kelvin?
Add 273.15 to degrees Celsius. Example: 0 °C is 273.15 K, and 20 °C is 293.15 K. The converter shows 273.15 K and 293.15 K.
Is a Celsius degree the same size as a kelvin?
A temperature interval of 1 °C equals an interval of 1 K. A temperature reading does not: 0 °C is 273.15 K, not 0 K.
What is absolute zero in Celsius?
Absolute zero is 0 K, which is −273.15 °C. The converter shows -273.15 C for 0 K and 0.00 K for −273.15 °C.