Celsius to Kelvin: The Complete Guide
Kelvin (K) is the SI base unit of temperature, used in science, engineering, and physics. Unlike Celsius and Fahrenheit, Kelvin has no negative values — 0 K is absolute zero, the theoretical lowest possible temperature (−273.15 °C). Converting Celsius to Kelvin is straightforward but important to get right in scientific contexts.
The Conversion Formula
K = °C + 273.15This is a simple addition — the scales have the same degree size, just a different zero point. Kelvin degrees are never written with the ° symbol.
Scientific Reference Table
- −273.15 °C = 0 K (absolute zero)
- −196 °C = 77.15 K (liquid nitrogen boiling point)
- 0 °C = 273.15 K (water freezing)
- 20 °C = 293.15 K (room temperature)
- 37 °C = 310.15 K (body temperature)
- 100 °C = 373.15 K (water boiling at sea level)
- 5,500 °C ≈ 5,773 K (surface of the Sun)
Why Kelvin Is Used in Science
Physical laws involving temperature (ideal gas law, Planck's radiation law, Stefan-Boltzmann law) require absolute temperature in Kelvin. A gas at 200 K has exactly half the thermal energy of a gas at 400 K — this proportional relationship breaks down if you use Celsius or Fahrenheit. Always use Kelvin in thermodynamic calculations.
Convert any temperature instantly: Free Celsius to Kelvin converter