Temperature converter
Convert between Celsius, Fahrenheit, Kelvin and Rankine.
Fill in the fields and the result will appear here automatically.
Converts temperature between Celsius, Fahrenheit, Kelvin and Rankine. Temperature scales are offset from one another rather than simple multiples, which is why converting by multiplication alone gives the wrong answer.
How it works
Formula and logic
Every scale converts through kelvin using a factor and an offset.
Example
0 °C is 32 °F, and 100 °C is 212 °F.
Fields and units
- Temperature — in the selected source unit
- From unit — list option
- To unit — list option
How to use
- — Enter the temperature.
- — Pick the source scale.
- — Pick the target scale.
Method and limitations
- Calculation method
- Formula and logic
- Data or methodology source
- NIST: temperature scales
- Limitation
- The result is a rounded unit conversion. Check the entered value and selected units.
FAQ
Why can temperature not be converted by a single factor?
Celsius and Fahrenheit start at different points, so a conversion needs both a scale factor and an offset. Only Kelvin and Rankine share the absolute zero point.
Where do Celsius and Fahrenheit meet?
At −40. It is the only temperature where both scales read the same number.
What is Rankine?
An absolute scale using Fahrenheit-sized degrees: 0 °Ra is absolute zero and 491.67 °Ra is the freezing point of water.
Can I enter temperatures below absolute zero?
The algebraic conversion accepts finite values even below 0 K. Such a value does not represent an ordinary physical temperature below absolute zero: 0 K = −273.15 °C = −459.67 °F. The tool does not validate thermodynamic applicability.