Convert Celsius to Kelvin
Celsius to Kelvin is the conversion scientists use most, since Kelvin is the base temperature unit in physics and chemistry. It's the simplest of the temperature conversions — just an offset, with no scaling — because a Celsius degree and a kelvin are exactly the same size.
Celsius to Kelvin conversion table
| Celsius (°C) | Kelvin (K) |
|---|---|
| 1 | 274.15 |
| 2 | 275.15 |
| 3 | 276.15 |
| 5 | 278.15 |
| 10 | 283.15 |
| 20 | 293.15 |
| 50 | 323.15 |
| 100 | 373.15 |
| 500 | 773.15 |
| 1,000 | 1,273.15 |
The formula
To convert Celsius to Kelvin, add 273.15:
K = °C + 273.15
Unlike Celsius-to-Fahrenheit, there's no multiplying step here — a Celsius degree and a kelvin cover the same size of temperature change. The only difference between the two scales is where they start counting from: Celsius sets its zero at water's freezing point, while Kelvin sets its zero at absolute zero, the coldest temperature possible.
Worked example: Convert a warm 37°C (body temperature) to Kelvin:
37 + 273.15 = 310.15 K
Two more anchor points: 0°C = 273.15 K (water freezes), and 100°C = 373.15 K (water boils).
You'll reach for this conversion in lab work, thermodynamics formulas, and any scientific calculation that requires an absolute temperature scale rather than an everyday one.
Frequently asked questions
What is the Celsius to Kelvin formula?
Add 273.15: K = °C + 273.15. There's no multiplication step, since a change of one degree Celsius equals a change of one kelvin — only the starting point (the zero) is different.
What is 0°C in Kelvin?
273.15 K — the temperature at which water freezes. This is the anchor point most worth remembering, since it shows exactly how far Kelvin's zero sits below Celsius's zero.
Why is there no degree symbol on Kelvin?
Kelvin measures temperature from absolute zero rather than from an arbitrary point like water's freezing point, so it's treated as an absolute unit, not a degree scale. Write '310.15 K', never '310.15°K' or 'degrees Kelvin'.