Celsius is a temperature scale with water freezing at 0 C and boiling at 100 C.
Celsius to Kelvins Converter — C to K
Convert Celsius (C) to Kelvin (K) using the exact temperature formula. See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Celsius to Kelvins 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.
Kelvin is the SI absolute temperature scale.
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 Celsius to Kelvins
Celsius and Kelvin are the two everyday temperature scales, and converting between them matters for reading weather forecasts, following recipes, and understanding scientific data across regions. Celsius is typically associated with standard temperature scale in nearly every country except the United States, while Kelvin is typically associated with standard scientific temperature unit worldwide.
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 × 9/5) + 32 = 273.15 °F
0 celsius = 273.15 kelvins.
Real-world example
(0 × 9/5) + 32 = 273.15 °F
0 celsius = 273.15 kelvins.
Conversion table
| Celsius (C) | Kelvin (K) |
|---|---|
| -40 C | 233.15 K |
| -20 C | 253.15 K |
| 0 C | 273.15 K |
| 20 C | 293.15 K |
| 37 C | 310.15 K |
| 100 C | 373.15 K |
Reverse conversion: Kelvin to Celsius
(274.15 − 32) × 5/9 = 1 °C
274.15 kelvins = 1 celsius.
Convert the source temperature to Kelvin, then convert Kelvin to the target scale.
For a page dedicated to this direction, see Kelvin to Celsius.
Celsius vs. Kelvin
| Aspect | Celsius | Kelvin |
|---|---|---|
| Family | SI-derived temperature scale | SI base unit |
| Typical use | Weather forecasting and climate reporting worldwide | Scientific and engineering temperature measurement (physics, chemistry) |
| Where it's used | Standard temperature scale in nearly every country except the United States | Standard scientific temperature unit worldwide |
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.
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.
Celsius — sources
- BIPM SI Brochure — Celsius temperature scale — Formal definition tying Celsius to Kelvin.
Kelvin — sources
- BIPM — The kelvin (SI base unit) — Current definition and history of the kelvin.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many kelvins are in 1 celsius?
1 celsius equals 274.15 kelvins, using the offset temperature formula rather than an estimate.
How do I convert celsius to kelvin?
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 kelvin back to celsius?
Use the reverse factor: 1 kelvin equals -272.15 celsius. You can also use the swap control in the converter above to flip the direction instantly.
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.
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.
Is the Celsius to Kelvin 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 celsius still used today?
Standard temperature scale in nearly every country except the United States