Kelvin to Celsius Converter (K to °C)
Enter one temperature and see K, °C, and °F together.
Kelvin to Celsius and Celsius to Kelvin formulas
For an actual temperature, subtract 273.15 to convert kelvin to Celsius: °C = K − 273.15. Add the same offset in reverse: K = °C + 273.15. Fahrenheit also needs a scale factor: °F = K × 9/5 − 459.67.
Temperature differences use different arithmetic. A change of 1 K is exactly the same size as a change of 1 °C, while a change of 1 K equals a change of 1.8 °F. The mode switch keeps that interval math separate from actual thermometer values.
Kelvin to Celsius conversion chart
These are actual temperatures. Kelvin is written with K and no degree sign.
| Kelvin | Celsius | Fahrenheit |
|---|---|---|
| 0 K | -273.15 °C | -459.67 °F |
| 77 K | -196.15 °C | -321.07 °F |
| 100 K | -173.15 °C | -279.67 °F |
| 200 K | -73.15 °C | -99.67 °F |
| 273.15 K | 0 °C | 32 °F |
| 298.15 K | 25 °C | 77 °F |
| 300 K | 26.85 °C | 80.33 °F |
| 310.15 K | 37 °C | 98.6 °F |
| 373.15 K | 100 °C | 212 °F |
| 500 K | 226.85 °C | 440.33 °F |
Absolute zero, suffixes, and rounding
Absolute mode rejects values below 0 K, −273.15 °C, or −459.67 °F. Difference mode allows negative changes because they describe cooling rather than a temperature below absolute zero.
Type a suffix such as 300 K, 25 C, or 77°F to identify the source scale. Bare numbers use the selected default. Display rounding never changes the conversion formula or the precision of the original measurement.
Frequently asked questions
How do I convert Kelvin to Celsius?
Subtract 273.15 from the kelvin value: °C = K − 273.15. For example, 300 K equals 26.85 °C.
How do I convert Celsius to Kelvin?
Add 273.15 to the Celsius value: K = °C + 273.15. For example, 25 °C equals 298.15 K.
Is a change of 1 K equal to a change of 1 °C?
Yes. Kelvin and Celsius intervals have the same size, so Δ1 K equals Δ1 °C. That temperature change equals Δ1.8 °F. Use Temperature difference mode for changes rather than thermometer readings.
Can Kelvin be negative?
Not for ordinary absolute thermodynamic temperature. This converter rejects an absolute result below 0 K, equivalent to −273.15 °C or −459.67 °F. A negative temperature difference is valid.
Should I write degrees Kelvin or °K?
No. The SI unit name is kelvin and its symbol is K, without the word degree or a degree sign. Write 300 K, not 300 °K.
Can I paste a list with mixed temperature units?
Yes. Batch mode accepts up to 100 non-empty lines. Add K, C, °C, F, or °F to each line; a suffix overrides the selected default scale. Any invalid line blocks the whole copied table.
Sources and method
The calculator implements the SI kelvin–Celsius offset and exact interval relationships described by the following references.