Kelvin Temperature Converter — K to Celsius and Fahrenheit
- 0 Kelvin = absolute zero = -273.15°C = -459.67°F. To convert: K = °C + 273.15. Room temperature is 293–298 K. Body temperature is 310 K.
Table of Contents
0 Kelvin = -273.15°C = -459.67°F. Kelvin is the SI base unit for temperature — used in science, physics, engineering, and any field where absolute thermodynamic temperature matters. Select the Temperature tab in the converter above to convert between Kelvin, Celsius, and Fahrenheit.
The Kelvin scale starts at absolute zero — the coldest possible temperature. Unlike Celsius and Fahrenheit, Kelvin has no negative values. 0 K is the floor; there is nothing colder.
Kelvin to Celsius and Fahrenheit — Formula
Kelvin to Celsius: °C = K − 273.15
Celsius to Kelvin: K = °C + 273.15
Kelvin to Fahrenheit: °F = (K − 273.15) × 9/5 + 32
The Kelvin scale uses the same degree size as Celsius — just shifted by 273.15. This means temperature differences in Kelvin and Celsius are identical: a 10 K change is the same as a 10°C change.
Common Kelvin Reference Points
| Kelvin | Celsius | Fahrenheit | What It Is |
|---|---|---|---|
| 0 K | -273.15°C | -459.67°F | absolute zero |
| 77 K | -196°C | -320°F | liquid nitrogen boiling |
| 195 K | -78°C | -109°F | dry ice sublimation |
| 233 K | -40°C | -40°F | F = C crossover point |
| 273.15 K | 0°C | 32°F | water freezing |
| 293 K | 20°C | 68°F | room temperature |
| 298 K | 25°C | 77°F | standard lab temperature |
| 310 K | 37°C | 98.6°F | human body temperature |
| 373.15 K | 100°C | 212°F | water boiling (sea level) |
| 5,778 K | 5,505°C | 9,940°F | surface of the Sun |
Why Kelvin Is Used in Science
Gas laws, blackbody radiation, thermodynamics, and many chemistry equations require absolute temperature — temperature measured from absolute zero, not from an arbitrary reference like the freezing point of water.
Examples: the ideal gas law (PV = nRT) requires T in Kelvin. Wien's displacement law (for blackbody radiation peak wavelength) requires K. The Boltzmann constant relates energy to temperature in Kelvin.
In everyday life outside science, Kelvin appears in photography (color temperature of light — a 6,500 K light source is daylight, 2,700 K is warm incandescent) and in refrigeration and HVAC engineering.
Kelvin in Color Temperature (Photography)
Light color temperature is measured in Kelvin even for everyday contexts like light bulbs and camera white balance:
- 1,800 K — candlelight (very warm/orange)
- 2,700 K — warm white LED / incandescent bulb
- 4,000 K — cool white / neutral
- 5,500–6,500 K — daylight / sunny day
- 7,500–10,000 K — overcast sky / shade (blue-tinted)
Camera white balance settings in Kelvin tell the camera what color to consider "neutral white" — higher K values shift toward blue, lower K values shift toward orange/warm tones.
Convert Kelvin, Celsius and Fahrenheit
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Open Unit Converter FreeFrequently Asked Questions
What is 0 Kelvin in Celsius?
0 K = -273.15°C = -459.67°F. This is absolute zero — the lowest possible temperature.
How do you convert Kelvin to Celsius?
Subtract 273.15 from the Kelvin value. Example: 300 K − 273.15 = 26.85°C.
What is room temperature in Kelvin?
Standard room temperature is approximately 293–298 K (20–25°C / 68–77°F). Scientific "standard temperature" is defined as 298 K (25°C).
Is Kelvin warmer or colder than Celsius at the same number?
At the same number, Kelvin is much colder. 100 K = -173.15°C. Celsius values below -273.15 do not exist — that would be below absolute zero. Celsius values below 0 are cold but above absolute zero; Kelvin values are always 273.15 higher than the same Celsius temperature.
