Complete guide: Temperature
Updated:
Fahrenheit = Celsius × 9/5 + 32. Celsius = (Fahrenheit − 32) × 5/9. Kelvin = Celsius + 273.15. These are absolute temperatures, not temperature differences: a thermal change does not add the 32 or 273.15 offset.
Absolute zero is 0 K, −273.15 °C or −459.67 °F. Values below these limits are rejected. Kelvin is written without a degree symbol. The converter does not interpret fever, food storage or safety conditions.
Equivalences use internal precision and display up to ten significant digits. Very small quantities use scientific notation so they do not appear to be zero. Changing units does not change the object or replace a real measurement.
Sources and conversion conventions
Document review: 2026-10-24
How it works
- 1Select units or the applicable reference.
- 2Enter the quantity or size you want to compare.
- 3Check the breakdown and equivalence conventions.
Frequently asked questions
Why are negative kelvin rejected?
This tool uses the ordinary thermodynamic scale, whose lower bound is 0 K.
Can I share a conversion with its values?
Yes. The link retains quantity, units and all entered options; recipients can reproduce the result and edit the inputs.