To convert Celsius to Kelvin (°C to K), multiply by 1 then + 273.15. 1 Celsius equals 274.15 K.
| Celsius | Kelvin |
|---|---|
| 1 Celsius | 274.15 K |
| 2 Celsius | 275.15 K |
| 5 Celsius | 278.15 K |
| 10 Celsius | 283.15 K |
| 25 Celsius | 298.15 K |
| 50 Celsius | 323.15 K |
| 100 Celsius | 373.15 K |
| 250 Celsius | 523.15 K |
| 500 Celsius | 773.15 K |
| 1000 Celsius | 1,273.15 K |
Definition: Water freezes at 0°C and boils at 100°C, at standard atmospheric pressure.
History: Swedish astronomer Anders Celsius proposed the scale in 1742 - but his original version was backwards. He set 0° at boiling and 100° at freezing, reasoning that Swedish winters would rarely need negative numbers if cold meant high numbers instead. He died just two years later, and the scale was flipped to the version used today - credit is usually given to the botanist Carl Linnaeus, though some historians think it may actually have been Daniel Ekström, the instrument-maker who built both their thermometers.
Current use: Nearly every country on Earth uses Celsius for everyday temperature - weather, cooking, body temperature. The US is the largest holdout still using Fahrenheit for daily life.
Definition: Kelvin measures temperature starting from absolute zero - the coldest temperature theoretically possible, where atomic motion itself grinds to a stop. Each Kelvin degree is the exact same size as a Celsius degree; the scale is just shifted so 0 means no heat energy left, instead of water freezing.
History: Named after William Thomson, later Lord Kelvin, who worked out the concept of absolute zero from thermodynamics in 1848. He realized temperature scales built around water's freezing and boiling points were somewhat arbitrary, and proposed one anchored to something more fundamental instead: the total absence of thermal energy.
Current use: You'll never hear a weather forecast in Kelvin, but you'll find it in nearly every physics and chemistry equation, and it's the standard unit for describing how hot a star is - the Sun's surface, for instance, is about 5,778 K.