How it works
Convert a temperature between the Celsius and Fahrenheit scales used for weather and cooking, and the absolute Kelvin and Rankine scales used in science and engineering.
Temperature scales have different zero points, so conversion is not a simple multiplication. Celsius and Kelvin share the same degree size, as do Fahrenheit and Rankine; one Celsius degree equals 1.8 Fahrenheit degrees.
Absolute zero, the lowest possible temperature, is 0 K, −273.15 °C, −459.67 °F and 0 °R. The converter rejects values below it.
Formula
°F = °C × 9/5 + 32; °C = (°F − 32) × 5/9; K = °C + 273.15; °R = °F + 459.67
Questions people ask
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 (1.8) and add 32. For example, 20 °C × 1.8 + 32 = 68 °F. A quick mental estimate is to double the Celsius value and add 30.
At what temperature are Celsius and Fahrenheit equal?
At −40. Minus 40 °C is exactly −40 °F.
Why is Kelvin written without a degree sign?
Kelvin is an absolute SI base unit, so since 1967 it is written simply as K (for example 300 K), not °K.
What is normal body temperature in Celsius?
The traditional reference of 98.6 °F is 37 °C, though typical healthy body temperature varies by person and time of day, roughly 36.1–37.2 °C.