# British thermal unit (IT) conversions

The British thermal unit (IT) conversion selector on this page selects the energy measurement unit to convert to starting from British thermal units (IT) (BTU). To make a conversion starting from a unit of energy other than British thermal unit (IT), simply click on the "Reset" button.

## About British thermal unit (IT)

The **British thermal unit (IT)** is a unit of energy equal to 1,055.05585 joules (1 BTU (IT) = 1,055.05585 J), the SI derived unit of energy.

The British thermal unit (IT) is also equal to 1.05505585 kilojoules (kJ), or 252.164401 calories (thermochemical) (cal), or 0.252164401 kilocalories (thermochemical) (kcal), or 0.5555556 Celsius heat units (IT) (CHU), or 0.29307107 watt hours (Wh) or 0.00029307107 kilowatt hours (kWh).

The British thermal unit is the energy required to increase the temperature of one pound of water by one degree Fahrenheit (0.556 degrees Celsius) at a constant pressure of one atmosphere.

The **British thermal unit definition** varies as follows:

- The British thermal unit (IT) (BTU) is equal to 1,055.05585262 joules
- The British thermal unit (ISO) (BTU) is equal to 1,055.056 joules
- The British thermal unit (th) (BTU) is equal to about 1,054.35026444 joules
- The British thermal unit (mean) (BTU) is equal to about 1,055.87 joules
- The British thermal unit (39 °F) (BTU) is equal to about 1,059.67 joules
- The British thermal unit (59 °F) (BTU) is equal to 1,054.804 joules
- The British thermal unit (60 °F) (BTU) is equal to about 1,054.68 joules
- The British thermal unit (63 °F) (BTU) is equal to about 1,054.6 joules

The **most common BTU multiples** are:

- One thousand British thermal units (MBTU, MBtu, e3BTU, BTUE3), equal to 1,000 BTU
- One million British thermal units (MMBTU, MMBtu, e6BTU, BTUE6), equal to 1,000,000 BTU
- One therm, equal to 100,000 BTU
- One quad (energy) (or quadrillion BTU), equal to 10
^{15}BTU

The BTU is commonly used in the power generation, steam generation, heating and air conditioning industries. Usually, the BTU-IT is used in the European Union while the BTU-59 °F is used in the United States.

Symbol: BTU

Plural: British thermal units (IT)