Here are the primary conversion formulas.
Celsius to Fahrenheit:
(°C × 9/5) + 32 = °F
Fahrenheit to Celsius:
(°F − 32) × 5/9 = °C
Celsius to Kelvin:
°C + 273.15 = K
Kelvin to Celsius:
K − 273.15 = °C
Fahrenheit to Kelvin:
(°F − 32) × 5/9 + 273.15 = K
Kelvin to Fahrenheit:
(K − 273.15) × 9/5 + 32 = °F
Learn about the origin and common uses of each scale.
Celsius (°C)
The Celsius scale is part of the metric system. It defines 0°C as the freezing point of water and 100°C as the boiling point of water at one atmosphere of pressure. It's the most common scale used worldwide for everyday temperature measurement.
Fahrenheit (°F)
Used primarily in the United States, the Fahrenheit scale sets the freezing point of water at 32°F and the boiling point at 212°F. This places the two points exactly 180 degrees apart.
Kelvin (K)
Kelvin is the base unit of thermodynamic temperature in the International System of Units (SI). It is an absolute scale, where 0 K represents absolute zero—the point at which all thermal motion ceases. It's primarily used in scientific contexts. Note that it does not use the degree symbol.
Here are some common questions and answers about temperature conversion.
What is the easiest way to convert Celsius to Fahrenheit?
A quick mental shortcut is to double the Celsius temperature and add 30. It's not exact, but gives a good approximation for moderate temperatures.
Why is Kelvin used in science?
Because Kelvin is an absolute scale starting at 0 (absolute zero), it makes calculations in thermodynamics and physics much simpler, as there are no negative numbers.
At what temperature are Celsius and Fahrenheit equal?
-40 degrees. At this specific point, -40°C is equal to -40°F.
