To convert Kelvin to Celsius, subtract 273.15. Formula: °C = K − 273.15. Examples: 0 K = −273.15°C, 273.15 K = 0°C, 300 K = 26.85°C, 373.15 K = 100°C. No multiplication needed - the two scales have identical degree sizes.
- Formula: °C = K − 273.15 (just subtract the zero-point offset - no scaling).
- 0 K = −273.15°C - absolute zero, the physical minimum temperature.
- 273.15 K = 0°C - water freezes at standard pressure.
- A change of 1 K equals a change of 1°C - degree sizes are identical.
How to Use This Converter
Type any Kelvin value in the K field and the Celsius result appears instantly. You can also type in the °C field to convert back to Kelvin - it works in both directions without pressing a button.
How Do You Convert Kelvin to Celsius?
Subtract 273.15. Kelvin and Celsius use the same degree size, so no multiplication is needed. The only difference is the zero point: Kelvin starts at absolute zero (the lowest possible temperature), while Celsius starts at the freezing point of water.
$$°C = K - 273.15$$
Worked examples: 0 K = −273.15°C. 77.15 K = −196°C (liquid nitrogen). 273.15 K = 0°C. 298.15 K = 25°C. 300 K = 26.85°C. 310.15 K = 37°C. 373.15 K = 100°C.
Note: Kelvin values are always positive (or zero) because 0 K is the absolute minimum. A negative Kelvin temperature has no physical meaning.
How Do You Convert Celsius to Kelvin?
Add 273.15. See the dedicated Celsius to Kelvin converter for a Celsius-first reference table.
$$K = °C + 273.15$$
Worked examples: 0°C = 273.15 K. 25°C = 298.15 K. 37°C = 310.15 K. 100°C = 373.15 K.
Kelvin to Celsius Reference Table
Key scientific and physical fixed points converted using °C = K − 273.15:
| Kelvin (K) | Celsius (°C) | Context |
|---|---|---|
| 0 K | −273.15°C | Absolute zero |
| 4.2 K | −268.95°C | Liquid helium boiling point |
| 77.15 K | −196°C | Liquid nitrogen boiling point |
| 194.65 K | −78.5°C | Dry ice sublimation point |
| 233.15 K | −40°C | °C = °F crossover point |
| 273.15 K | 0°C | Water freezes |
| 293.15 K | 20°C | Room temperature |
| 298.15 K | 25°C | Standard state (chemistry) |
| 300 K | 26.85°C | Common thermodynamics reference |
| 310.15 K | 37°C | Normal body temperature |
| 373.15 K | 100°C | Water boils at sea level |
When Do You Need to Convert Kelvin to Celsius?
Scientific results and data tables often give temperatures in Kelvin. Converting back to Celsius makes the values intuitively understandable. Common situations:
- Reading scientific papers - experimental temperatures in physics and chemistry are often given in Kelvin; converting to Celsius gives an everyday sense of the scale.
- Thermodynamics homework - problems are solved in Kelvin; answers are sometimes requested in Celsius for context.
- Astronomy - stellar surface temperatures (e.g. the Sun ≈ 5778 K = 5504.85°C) are stated in Kelvin.
- Cryogenics - working with liquid nitrogen (77.15 K = −196°C) or liquid helium (4.2 K = −268.95°C) requires familiarity with both scales.
Frequently Asked Questions
How do you convert Kelvin to Celsius?
Subtract 273.15. Formula: °C = K − 273.15. Example: 373.15 K − 273.15 = 100°C (water boiling point). No multiplication is needed because Kelvin and Celsius have identical degree sizes.
What is 0 Kelvin in Celsius?
0 K = −273.15°C. This is absolute zero - the lowest possible temperature, where all classical thermal motion stops. It has been approached to within billionths of a degree but never fully reached.
What is 300 K in Celsius?
300 K = 26.85°C. Calculation: 300 − 273.15 = 26.85°C. This is approximately room temperature and is a common reference value in thermodynamics equations because it is conveniently close to 25°C (298.15 K).
Can Kelvin be negative?
No. Kelvin starts at absolute zero (0 K), the lowest possible temperature. There is no temperature below absolute zero in classical thermodynamics. If you get a negative Kelvin result, the input Kelvin value was below 273.15 K, meaning the Celsius equivalent is negative - which is valid - but the Kelvin value itself must always be ≥ 0.