# Celsius

Celsius or centigrade is a unit of measurement of temperature.

The freezing/melting point of water is about zero degrees celsius (0 °C) at a pressure of 1 atmosphere.

The boiling point of water is about on one hundred degrees celsius (100 °C) at a pressure of 1 atmosphere.

The exact values depend on the water composition (usually the amount of salt) and the air pressure.

Seawater contains salt and the freezing point is reduced below 0 °C.

When boiling water on a mountain above sea level the boiling point is reduced below 100 °C.

The symbol of Celsius degrees is °C.

## Celsius to Fahrenheit conversion

0 degrees Celsius is equal to 32 degrees Fahrenheit:

0 °C = 32 °F

The temperature T in degrees Fahrenheit (°F) is equal to the temperature T in degrees Celsius (°C) times 9/5 plus 32:

T(°F) = T(°C) × 9/5 + 32

#### Example

Convert 20 degrees Celsius to degrees Fahrenheit:

T(°F) = 20°C × 9/5 + 32 = 68 °F

## Celsius to Kelvin conversion

0 degrees Celsius is equal to 273.15 degrees Kelvin:

0 °C = 273.15 K

The temperature T in Kelvin (K) is equal to the temperature T in degrees Celsius (°C) plus 273.15:

T(K) = T(°C) + 273.15

#### Example

Convert 20 degrees Celsius to Kelvin:

T(K) = 20°C + 273.15 = 293.15 K

## Celsius to Rankine conversion

The temperature T in degrees Rankine (°R) is equal to the temperature T in degrees Celsius (°C) plus 273.15, times 9/5:

T(°R) = (T(°C) + 273.15) × 9/5

#### Example

Convert 20 degrees Celsius to degrees Rankine:

T(°R) = (20°C + 273.15) × 9/5 = 527.67 °R

## Celsius table

Celsius (°C) Fahrenheit (°F) Temperature
-273.15 °C -459.67 °F absolute zero temperature
0 °C 32.0 °F freezing/melting point of water
21 °C 69.8 °F room temperature
37 °C 98.6 °F average body temperature
100 °C 212.0 °F boiling point of water