Starting at Absolute Zero
Kelvin measures temperature from absolute zero — the point where molecular motion theoretically stops. Absolute zero is 0 K, which equals −273.15°C. Because the scale starts at the true bottom of temperature, Kelvin values are always non-negative.
Same Size as Celsius
A kelvin and a degree Celsius are the same size; only the starting point differs. To convert Celsius to Kelvin, add 273.15. To convert Kelvin to Celsius, subtract 273.15. No multiplier is needed.
Reference Points
| Kelvin | Celsius | Meaning |
|---|---|---|
| 0 | −273.15 | Absolute zero |
| 273.15 | 0 | Water freezes |
| 310.15 | 37 | Body temperature |
| 373.15 | 100 | Water boils |