kelvin (K)
1 kelvin = -272.15 degrees Celsius
What is kelvin?
Kelvin is the SI base unit of thermodynamic temperature, with its zero point at absolute zero. It is the standard in scientific and engineering fields where absolute temperature values are required, such as thermodynamics and astrophysics.
Notes: Base unit for temperature
Real-world uses
Kelvin is the SI base unit for thermodynamic temperature, used in physics, chemistry, and engineering. Colour temperature of lighting (e.g., 5000 K daylight, 2700 K warm white) is specified in kelvins. Cryogenics and astrophysics rely on kelvin exclusively.
History
Named after William Thomson, 1st Baron Kelvin, who proposed an absolute temperature scale in 1848. The scale's zero point represents absolute zero, where molecular motion reaches its minimum. It became an SI base unit in 1954.
Common mistakes
Writing "degrees Kelvin" or "°K"—kelvin uses no degree symbol and is written simply as "K." Also, confusing kelvin with Celsius: 0 K is absolute zero (−273.15°C), not the freezing point of water.
When is this conversion used?
This is the most common temperature conversion worldwide, needed for weather reports, cooking temperatures, and medical readings. Most of the world uses Celsius while the US primarily uses Fahrenheit.
How to convert kelvin to degree Celsius
Formula: °C = K − 273.15
Conversion formula (from base unit)
x * 1.0
Measurement standards
The kelvin is the SI base unit of thermodynamic temperature, defined by fixing the Boltzmann constant to exactly 1.380649 × 10⁻²³ joules per kelvin. This definition, adopted in 2019, decoupled the kelvin from the triple point of water.
Did you know?
The coldest temperature ever recorded on Earth was −89.2 °C (−128.6 °F) at the Soviet Vostok Station in Antarctica on 21 July 1983. In laboratories, scientists have cooled atoms to within billionths of a kelvin above absolute zero.
| kelvins | degrees Celsius |
|---|---|
| 0 | -273.15 |
| 10 | -263.15 |
| 20 | -253.15 |
| 25 | -248.15 |
| 37 | -236.15 |
| 50 | -223.15 |
| 100 | -173.15 |
| 200 | -73.15 |
| 500 | 226.85 |
Common values
| kelvins | degrees Celsius | |
|---|---|---|
| Water freezes | 273.15 kelvins | 0 degrees Celsius |
| Room temperature | 294.15 kelvins | 21 degrees Celsius |
| Human body | 310.15 kelvins | 37 degrees Celsius |
| Oven baking | 453.15 kelvins | 180 degrees Celsius |
| Water boils | 373.15 kelvins | 100 degrees Celsius |
Full kelvin conversion table
| Unit | Value | Factor |
|---|---|---|
| degree Celsius | 1 K = -272.15 °C | °C = K − 273.15 |
| degree Fahrenheit | 1 K = -457.87 °F | °F = K × 1.8 − 459.67 |
| degree Rankine | 1 K = 1.8 °R | °R = K × 9/5 |
| degree Réaumur | 1 K = -217.72 °Re | °Re = K × 0.8 − 218.52 |