Example 1 — Room temperature
- Value: 25 °C
- Direction: °C → K
298.15 K
A typical room temperature, often used as a reference point in chemistry.
Kelvin to Celsius converter
Type a temperature — you’ll get Kelvin and Celsius instantly, plus a little visual of how close you are to absolute zero.
We stick to the exact formula K = °C + 273.15 — no rounding shortcuts. Kelvin never goes negative, because 0 K is absolute zero. For weather or a recipe, grab the Celsius ↔ Fahrenheit converter instead.
Result
Enter a temperature value.
How results are calculated
°C → K: K = °C + 273.15.
K → °C: °C = K − 273.15.
A degree is exactly the same size on both scales — only the zero point moves. Negative Kelvin just doesn't exist in nature.
How to use the calculator
- Enter the temperature value to convert.
- Choose a direction: °C → K or K → °C.
- Click Calculate or watch the live result as you type.
- Check the scale visualization below the form — it shows how far you are from absolute zero.
Usage examples
Example 2 — Absolute zero
- Value: 0 K
- Direction: K → °C
−273.15 °C
The lowest theoretically possible temperature — the zero point of the Kelvin scale.
Example 3 — Body temperature
- Value: 37 °C
- Direction: °C → K
310.15 K
Useful for thermal descriptions in physiology or medical devices.
FAQ
How do I convert Kelvin to Celsius?
°C = K − 273.15 (and the other way: K = °C + 273.15). The gap between the scales is always exactly 273.15 — the “degree size” is the same.
What is absolute zero, in plain terms?
0 K, or −273.15 °C — you can’t go lower because particle motion stops. That’s why Kelvin never goes negative.
Why do I get an error for negative Kelvin?
Because those temperatures don’t exist. Rather than invent a nonsense number, the converter just refuses.
Where is Kelvin actually used?
Science and engineering: physics, chemistry, astronomy, LED color temperature — anywhere absolute temperature matters more than “degrees above freezing.”
Is 1 °C the same size as 1 K?
Yes — a 1 °C change is exactly 1 K. Only the zero point differs.
How many Kelvin is room temperature?
Around 20–22 °C → roughly 293–295 K.
Can I type decimals?
Yep — e.g. 293.15 with a dot or a comma.
What if I also need Fahrenheit?
Open Celsius ↔ Fahrenheit — that’s the everyday weather/cooking one.