Temperature Converter

Convert between Celsius, Fahrenheit, Kelvin and Rankine. Pick any two scales; it runs entirely in your browser.

Temperature scales differ in two ways — the size of one degree and where zero sits — so every conversion is a multiply-and-add, not a single ratio. The core relationships are °F = °C × 1.8 + 32, K = °C + 273.15 and °R = °F + 459.67, and the live tool above uses these exact formulas.

Popular temperature conversions

The temperature scales

ScaleWhat it is
Celsius (°C)Celsius (centigrade) puts 0° at the freezing point of water and 100° at its boiling point at sea level. It is the everyday temperature scale used almost everywhere outside the United States.
Fahrenheit (°F)Fahrenheit puts water’s freezing point at 32° and its boiling point at 212° — a 180-degree span. It is the everyday scale in the United States and a few other territories.
Kelvin (K)The kelvin is the SI base unit of temperature. It starts at absolute zero (0 K = −273.15 °C) and uses the same degree size as Celsius, so it is written without a degree sign.
Rankine (°R)The Rankine scale starts at absolute zero like Kelvin but uses the Fahrenheit-sized degree (0 °R = −459.67 °F). It appears in some US engineering and thermodynamics work.