Convert celsius to kelvin instantly. Enter a value below, or use the formula and reference table further down the page.
In practice
Celsius-to-Kelvin is the simplest temperature conversion there is: add 273.15. Unlike Fahrenheit there is no scale factor, because a kelvin is exactly the same size as a degree Celsius — a rise of 1 K is a rise of 1°C. Water freezes at 273.15 K and boils at 373.15 K at standard pressure, and a comfortable 20°C room is 293.15 K. Kelvin has no degree symbol and zero is absolute zero (−273.15°C), so negative kelvin temperatures are impossible. Since 2019 the kelvin has been defined by fixing the Boltzmann constant rather than by water, which is why science and engineering use it. The same unit also appears in lighting, where 2700 K is warm white and 6500 K is daylight.
How to convert celsius to kelvin
Multiply by 1, then add 273.15.
K = (°C × 1) + 273.15Example: 10 °C = 283.15 K.
Celsius to Kelvin conversion table
| Celsius (°C) | Kelvin (K) |
|---|---|
| 1 °C | 274.15 K |
| 2 °C | 275.15 K |
| 3 °C | 276.15 K |
| 4 °C | 277.15 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 |
| 50 °C | 323.15 K |
| 100 °C | 373.15 K |
Frequently asked questions
How many kelvin is 1 degree Celsius?
1 degree Celsius equals 274.15 kelvin.
What is the formula to convert °C to K?
To convert °C to K, multiply by 1 and add 273.15. The full formula is: K = (°C × 1) + 273.15.
How do I convert kelvin back to celsius?
Use the same calculator above and type your value into the kelvin field instead — it converts in both directions. Or use the reverse formula: °C = (K − 273.15) ÷ 1.
Is the °C to K conversion exact?
The conversion factor used here (1) is the standard internationally defined value. Results on this page are rounded to four decimal places for readability.