BTU to Joules Converter

The BTU to Joules Converter converts energy from British Thermal Units (BTU) to joules (J) and kilojoules (kJ) using the International Table conversion factor 1 BTU = 1,055.06 J. The BTU is a cornerstone unit in HVAC engineering, heating, and the energy industry, especially in North America.

The British Thermal Unit was originally defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. Like the calorie (its metric counterpart, which heats one gram of water by one degree Celsius), the BTU connects thermal energy to a tangible physical process. The modern International Table BTU (BTU_IT) is precisely defined as 1,055.05585 J, commonly rounded to 1,055.06 J.

BTU is essential in the heating, ventilation, and air conditioning (HVAC) industry. Air conditioners are rated in BTU/hr, furnaces in BTU input/output, and natural gas is sold by the therm (100,000 BTU). Converting BTU to joules is necessary when integrating HVAC calculations with general physics or international engineering standards that use SI units.

In the energy sector, BTU serves as a common unit for comparing different fuel types. One cubic foot of natural gas contains approximately 1,030 BTU. One barrel of oil contains about 5.8 million BTU. These figures are routinely converted to joules or kilojoules for international energy reporting and carbon accounting.

Our converter provides results in both joules and kilojoules, accommodating laboratory-scale calculations as well as industrial-scale energy analysis. The conversion factor is standardized by NIST and ISO, ensuring consistency across applications.