Conversions
Celsius to Kelvin Converter
Convert Celsius to Kelvin (and back), with Fahrenheit and Rankine alongside. Rejects values below absolute zero.
Temperature input
Result
298.15 K
comfortable
- Celsius
- 25 C
- Kelvin
- 298.15 K
- Fahrenheit
- 77 F
- Rankine
- 536.67 R
Frequently Asked Questions about the Celsius to Kelvin Converter
How do I convert Celsius to Kelvin?
Add 273.15 to the Celsius value. So 0 C is 273.15 K, 25 C is 298.15 K, and 100 C is 373.15 K. To go from Kelvin back to Celsius, subtract 273.15.
Why is there no degree symbol with Kelvin?
Kelvin is an absolute unit, not a relative scale. By SI convention you write 273.15 K, not 273.15 deg K. Celsius and Fahrenheit are relative scales, so they keep the degree symbol.
What is absolute zero?
Absolute zero is the lowest possible temperature: 0 K, equal to -273.15 C or -459.67 F. At that point classical particle motion stops. The calculator rejects any input below absolute zero.
When is Kelvin used instead of Celsius?
Scientific and engineering work uses Kelvin because ratios and laws (ideal gas law, blackbody radiation, color temperature for displays and lighting) need an absolute scale. Daily weather and cooking stick with Celsius or Fahrenheit.
What is the surface temperature of the Sun in Kelvin?
About 5,778 K (5,505 C / 9,941 F). That is the effective temperature of the photosphere; the core is millions of degrees and the corona is in the millions of K too, but the visible surface is in the high single-digit thousands.