BTU to Millijoule Converter

A British Thermal Unit (BTU) is a unit of energy equal to approximately 1,055 joules. It represents the amount of energy needed to raise the temperature of one pound of water by one degree Fahrenheit at standard atmospheric pressure.

The BTU was developed in the 19th century as part of the British Imperial system for measuring heat energy. It became standard in heating, ventilation, and air conditioning (HVAC) applications in countries using imperial units, particularly for rating heating and cooling equipment capacity.

BTUs are extensively used in the United States for HVAC system ratings, heating and cooling equipment specifications, and energy content of fuels. They're standard for furnace output ratings, air conditioner capacity, water heater specifications, and natural gas energy content measurements.

A millijoule (mJ) is a unit of energy equal to one thousandth of a joule (10⁻³ J). It represents small amounts of energy, typically found in electronic circuits, small mechanical systems, and precision energy measurements.

The millijoule became important with the development of precision electronics and small-scale energy measurements. It was particularly useful for measuring energy in electronic pulses, small mechanical impacts, and low-energy physical and chemical processes.

Millijoules are used in electronics for measuring pulse energy, in precision mechanics for small impact measurements, in laser technology for pulse energy, and in materials testing for small-scale energy absorption measurements.