Celsius to Kelvin Converter
Convert Celsius to Kelvin instantly. Free online temperature converter with common values and the conversion formula.
Formula
K = °C + 273.15
Common Conversions
How to Convert Celsius to Kelvin
Add 273.15 to Celsius. Formula: K = °C + 273.15. So 25 °C = 298.15 K. Kelvin uses absolute zero (-273.15 °C, the theoretical lowest possible temperature) as 0 K, but uses the same degree size as Celsius.
Kelvin is the SI base unit for temperature, used in scientific contexts where absolute temperature matters (thermodynamics, gas law calculations, astronomy). Notice no '°' symbol - kelvin is just 'K'. Common reference points: 0 K (absolute zero, -273.15 °C), 273.15 K (water freezing, 0 °C), 373.15 K (water boiling, 100 °C).
Common Celsius to Kelvin Conversions
| Celsius | Kelvin |
|---|---|
| -273.15 °C (abs zero) | 0 K |
| -100 °C | 173.15 K |
| 0 °C (freezing) | 273.15 K |
| 20 °C (room) | 293.15 K |
| 25 °C | 298.15 K |
| 100 °C (boiling) | 373.15 K |
| 1000 °C | 1273.15 K |
| 5500 °C (sun surface) | 5773.15 K |
Frequently Asked Questions
Why is Kelvin the SI temperature unit?
Because it's based on absolute zero, all values are positive numbers. This avoids negative-number issues in physics calculations. The kelvin scale was adopted as SI in 1954; the size of a kelvin is identical to a degree Celsius for ease of conversion.
Should it be °K or just K?
Just K. The degree symbol was officially dropped in 1967. So write '298 K' not '298 °K'. Same convention applies to all kelvin temperatures.
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