Celsius to Kelvin (°C to K)
0 °C = 273.15 K
Formula: K = °C + 273.15
How to convert Celsius to Kelvin
K = °C + 273.15
To convert, add 273.15. Example: 180 °C → 453.15 K.
Since 2019 the kelvin is defined via the Boltzmann constant; 0 °C is exactly 273.15 K, and a change of 1 °C equals a change of 1 K.
Used in physics, chemistry and engineering, where the kelvin is the SI unit of temperature and absolute zero is 0 K.
Mental shortcut: add 273 (for most practical work) (is off by just 0.15 K).
Celsius to Kelvin conversion chart
| Celsius | Kelvin |
|---|---|
| −273.15 °C | 0 K |
| −50 °C | 223.15 K |
| −45 °C | 228.15 K |
| −40 °C | 233.15 K |
| −35 °C | 238.15 K |
| −30 °C | 243.15 K |
| −25 °C | 248.15 K |
| −20 °C | 253.15 K |
| −15 °C | 258.15 K |
| −10 °C | 263.15 K |
| −5 °C | 268.15 K |
| 0 °C | 273.15 K |
| 5 °C | 278.15 K |
| 10 °C | 283.15 K |
| 15 °C | 288.15 K |
| 20 °C | 293.15 K |
| 25 °C | 298.15 K |
| 30 °C | 303.15 K |
| Celsius | Kelvin |
|---|---|
| 35 °C | 308.15 K |
| 40 °C | 313.15 K |
| 45 °C | 318.15 K |
| 50 °C | 323.15 K |
| 55 °C | 328.15 K |
| 60 °C | 333.15 K |
| 65 °C | 338.15 K |
| 70 °C | 343.15 K |
| 75 °C | 348.15 K |
| 80 °C | 353.15 K |
| 85 °C | 358.15 K |
| 90 °C | 363.15 K |
| 95 °C | 368.15 K |
| 100 °C | 373.15 K |
| 200 °C | 473.15 K |
| 300 °C | 573.15 K |
| 500 °C | 773.15 K |
| 1,000 °C | 1,273.15 K |
Values rounded to 2 decimal places (4 below 1). Use the converter above for more precision.
Frequently asked questions
What is the formula to convert Celsius to Kelvin?
K = °C + 273.15. In words: add 273.15. For example, 180 °C → 453.15 K. Since 2019 the kelvin is defined via the Boltzmann constant; 0 °C is exactly 273.15 K, and a change of 1 °C equals a change of 1 K.
How do I convert degrees Celsius to kelvins?
Use K = °C + 273.15: add 273.15. Example: 180 °C → 453.15 K.
Is there a quick way to estimate °C to K in your head?
Yes — add 273 (for most practical work). This is off by just 0.15 K. Use the exact formula (K = °C + 273.15) when precision matters.