British Thermal Units to Calories Converter

To convert a measurement in british thermal units to calories, multiply the value by 252.164401. The conversion factor comes from the relationship between both units and the joule.

For example, to convert 5 BTU to calories: 5 × 252.164401 = 1,260.822 cal.

A British thermal unit (BTU) is the energy needed to raise the temperature of one pound of water by one degree Fahrenheit, about 1,055 joules. The BTU arose from imperial heating and steam engineering. It remains the dominant unit for heating, ventilation, and air-conditioning capacity in the United States, where furnaces and air conditioners are rated in BTU.

Common uses of british thermal units include: Air conditioner and furnace ratings; Heating and cooling load calculations; Natural gas and fuel energy content; HVAC system sizing in the US.

A calorie (small calorie) is the energy needed to raise the temperature of one gram of water by one degree Celsius, defined as exactly 4.184 joules. The calorie originated in early-19th-century thermodynamics. The thermochemical calorie, fixed at exactly 4.184 J, is the modern standard, though it is often confused with the larger food Calorie (kilocalorie).

Common uses of calories include: Chemistry and thermodynamics; Heat-of-reaction measurements; Physics heat-transfer problems; Historical energy references.

Here are some common values converted:

1 BTU = 252.164401 cal 5 BTU = 1,260.822 cal 10 BTU = 2,521.644 cal 50 BTU = 12,608.22 cal 100 BTU = 25,216.4401 cal