temperature · International · Modern
Celsius temperature is defined from thermodynamic temperature by t/°C = T/K - 273.15.
Converter
temperature · International · Modern
kelvin
Kexact
- Record
- M024
- Definition quality
- Standardized
- Conversion mode
- multiplicative
- Calculator
- Fully calculable
None identified for current SI definition; name etymology not researched in this batch.
Definition
SI base unit of thermodynamic temperature. The Boltzmann constant is fixed exactly at 1.380649×10^-23 J/K.
Reference value
One kelvin is equal to 1 kelvin.
History & use
From 1954 the kelvin was tied to the triple point of water; the 2019 SI revision instead fixed the Boltzmann constant.
Modern use
International SI base unit for thermodynamic temperature.
Did you know?
The triple point of water remains an important practical reference, but it no longer defines the kelvin.
Sources & evidence
Source tier Tier A · confidence High
- Definition Source — https://www.bipm.org/en/measurement-units/si-defining-constants
- History Source — https://www.nist.gov/nist-museum/defining-international-system-units-si
- Modern Use Source — https://www.bipm.org/en/measurement-units/si-base-units
- Trivia Source — https://www.nist.gov/nist-museum/defining-international-system-units-si
Related measurements
temperature · International / Europe · Modern / historical
Fahrenheit temperature converts to Celsius by t°C = (t°F - 32)×5/9; temperature intervals scale by 5/9.