Kelvin is the SI absolute temperature scale.
Kelvins to Celsius Converter — K to C
Convert Kelvin (K) to Celsius (C) using the exact temperature formula. See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Kelvins to Celsius converter
Converter
Temperature Converter
Convert Celsius, Fahrenheit, Kelvin, Rankine, Delisle, Newton, Reaumur, and Romer.
Context values
Some unit families need one extra value for a physically accurate result.
Celsius is a temperature scale with water freezing at 0 C and boiling at 100 C.
Convert the source temperature to Kelvin, then convert Kelvin to the target scale.
Temperature conversion uses Kelvin as the intermediate absolute scale.
Reserved above the conversion cards and below the converter.
About Converting Kelvins to Celsius
Kelvin and Celsius are the two everyday temperature scales, and converting between them matters for reading weather forecasts, following recipes, and understanding scientific data across regions. Kelvin is typically associated with standard scientific temperature unit worldwide, while Celsius is typically associated with standard temperature scale in nearly every country except the United States.
Formula
Convert the source temperature to Kelvin, then convert Kelvin to the target scale.
Both scales are converted through Kelvin as a common absolute reference point.
Simple example
(0 − 32) × 5/9 = -273.15 °C
0 kelvins = -273.15 celsius.
Real-world example
(0 − 32) × 5/9 = -273.15 °C
0 kelvins = -273.15 celsius.
Conversion table
| Kelvin (K) | Celsius (C) |
|---|---|
| -40 K | -313.15 C |
| -20 K | -293.15 C |
| 0 K | -273.15 C |
| 20 K | -253.15 C |
| 37 K | -236.15 C |
| 100 K | -173.15 C |
Reverse conversion: Celsius to Kelvin
(-272.15 × 9/5) + 32 = 1 °F
-272.15 celsius = 1 kelvin.
Convert the source temperature to Kelvin, then convert Kelvin to the target scale.
For a page dedicated to this direction, see Celsius to Kelvin.
Kelvin vs. Celsius
| Aspect | Kelvin | Celsius |
|---|---|---|
| Family | SI base unit | SI-derived temperature scale |
| Typical use | Scientific and engineering temperature measurement (physics, chemistry) | Weather forecasting and climate reporting worldwide |
| Where it's used | Standard scientific temperature unit worldwide | Standard temperature scale in nearly every country except the United States |
Understanding the Kelvin
Kelvin (K) measures temperature. The kelvin is the SI base unit of thermodynamic temperature; 0 K (absolute zero) is the theoretical absence of thermal energy. It is classified as a SI base unit.
Where it's used: Standard scientific temperature unit worldwide
Uses of the Kelvin today
- Scientific and engineering temperature measurement (physics, chemistry)
- Color temperature specifications (lighting, displays)
- Cryogenics and low-temperature physics
History of the Kelvin
The kelvin scale was proposed by William Thomson (Lord Kelvin) in 1848, building on Sadi Carnot's thermodynamic work to define an absolute temperature scale independent of any particular substance's properties, with zero set at absolute zero.
Since 2019, the kelvin has been defined by fixing the Boltzmann constant at an exact value, tying it to a fundamental physical constant rather than the triple point of water used previously.
Historical origin. Kelvin was not the invention of a single named person; it developed through the process described above.
Understanding the Celsius
Celsius (C) measures temperature. Celsius is defined relative to the Kelvin scale, with 0 °C set at 273.15 K. It is classified as a SI-derived temperature scale.
Where it's used: Standard temperature scale in nearly every country except the United States
Uses of the Celsius today
- Weather forecasting and climate reporting worldwide
- Scientific and laboratory temperature measurement (alongside Kelvin)
- Cooking and food safety in most countries outside the US
History of the Celsius
Swedish astronomer Anders Celsius proposed a 100-point temperature scale in 1742, but his original scale ran in the opposite direction, with 0° at water's boiling point and 100° at freezing.
The scale was reversed to its modern orientation shortly after his death, commonly attributed to instrument maker Daniel Ekström and naturalist Carl Linnaeus around 1744-1745.
The scale was renamed from 'centigrade' to 'Celsius' by international agreement in 1948, and it is now formally defined as the Kelvin scale shifted by 273.15, rather than independently by the freezing and boiling points of water.
Historical origin. Celsius was not the invention of a single named person; it developed through the process described above.
Kelvin — sources
- BIPM — The kelvin (SI base unit) — Current definition and history of the kelvin.
Celsius — sources
- BIPM SI Brochure — Celsius temperature scale — Formal definition tying Celsius to Kelvin.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many celsius are in 1 kelvin?
1 kelvin equals -272.15 celsius, using the offset temperature formula rather than an estimate.
How do I convert kelvin to celsius?
Use the formula shown above: it involves both a multiplication and an addition/subtraction because the two scales don't share a common zero point.
How do I convert celsius back to kelvin?
Use the reverse factor: 1 celsius equals 274.15 kelvins. You can also use the swap control in the converter above to flip the direction instantly.
What is a kelvin?
Kelvin (K) measures temperature. The kelvin is the SI base unit of thermodynamic temperature; 0 K (absolute zero) is the theoretical absence of thermal energy. It is classified as a SI base unit.
What is a celsius?
Celsius (C) measures temperature. Celsius is defined relative to the Kelvin scale, with 0 °C set at 273.15 K. It is classified as a SI-derived temperature scale.
Is the Kelvin to Celsius conversion exact?
Yes. Both scales are formally defined relative to the Kelvin scale, so the conversion formula is exact — the only rounding involved is in how many decimal places you choose to display.
Where is the kelvin still used today?
Standard scientific temperature unit worldwide