Temperature conversion
-21 °C to K
252.15 K
-21 degrees Celsius = 252.15 kelvin. Exact factor: K = °C + 273.15.
Live converter
Edit either field — the other updates instantly. Type decimal values like 38.4.
The formula
K = °C + 273.15
Worked example: -21 + 273.15 = 252.15 K.
Values near -21 °C
| °C | K |
|---|---|
| -24 | 249.15 |
| -23 | 250.15 |
| -22 | 251.15 |
| -21this page | 252.15 |
| -20 | 253.15 |
| -19 | 254.15 |
| -18 | 255.15 |
Frequently asked
How do you convert degrees Celsius to kelvin?
Apply the formula K = °C + 273.15. Enter any value in the live converter above and the result updates as you type.
What is -21 °C in K?
-21 °C equals 252.15 K. The reference table below shows the values immediately around -21 °C.
Why does temperature conversion add 32?
The two scales have different zero points and step sizes. Water freezes at 32 °F but 0 °C, so the formula rescales by 5/9 and shifts by the 32-degree offset.