Celsius (°C)
The degree Celsius (°C) is the SI unit for Celsius temperature, defined by t(°C) = T(K) − 273.15. A temperature difference of 1 °C is exactly 1 K.
Symbol: °C (ASCII: degC)
Quantity: thermodynamic temperature
SI relation: T(K) = t(°C) + 273.15 (exact, by definition)
Derivation: T(K) = t(°C) + 273.15 (exact, by definition)
Exact: yes, by definition
History
Anders Celsius proposed a 100-degree scale in 1742. Since 1954 it has been tied to the kelvin, and since the 2019 SI redefinition the kelvin is fixed through the Boltzmann constant.
Typical uses
- Weather, cooking and body temperature in most countries
- Laboratory and process temperatures
- Material and equipment ratings (e.g. 121 °C autoclave cycles)
Convert degrees Celsius to other units
| Conversion | 1 °C equals | Reverse |
|---|---|---|
| Celsius to Fahrenheit | 33.8 °F | Fahrenheit to Celsius |
| Celsius to Kelvin | 274.15 K | Kelvin to Celsius |
| Celsius to Rankine | 493.47 °R | Rankine to Celsius |
Open the Temperature Converter to convert any value between all units.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Section 2.3.1 and Table 4, degree Celsius.
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Celsius (°C). Retrieved October 17, 2026, from https://scientificconverters.com/units/celsius/
IEEE
Scientific Converters, "Celsius (°C)," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/units/celsius/