Convert energy units — joules, kilowatt-hours, calories, BTU, electron volts and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 BTU | 0.778171 ft·lb | |
| 0.01 BTU | 7.78171 ft·lb | |
| 0.1 BTU | 77.8171 ft·lb | |
| 1 BTU | 778.171 ft·lb | |
| 5 BTU | 3890.86 ft·lb | |
| 10 BTU | 7781.71 ft·lb | |
| 50 BTU | 38908.6 ft·lb | |
| 100 BTU | 77817.1 ft·lb | |
| 1000 BTU | 778171 ft·lb |
Formula: Foot-Pound = BTU × 778.2
Multiply any btu value by 778.2 to get foot-pound.
Reverse: BTU = Foot-Pound × 0.001285
Common btu values — factor: 1 BTU = 778.2 ft·lb
| BTU (BTU) | Foot-Pound (ft·lb) | Context |
|---|---|---|
| 1 BTU | 778.2 ft·lb | Match |
| 10 BTU | 7,782 ft·lb | 10 BTU |
| 100 BTU | 7.782e+04 ft·lb | Space heater second |
| 1,000 BTU | 7.782e+05 ft·lb | 1 kBTU |
| 3,412 BTU | 2.655e+06 ft·lb | 1 kWh |
| 1e+04 BTU | 7.782e+06 ft·lb | 10 kBTU |
| 1e+05 BTU | 7.782e+07 ft·lb | 1 therm |
| 1e+06 BTU | 7.782e+08 ft·lb | 1 MMBTU |
| 1e+07 BTU | 7.782e+09 ft·lb | 10 MMBTU |
| 1e+08 BTU | 7.782e+10 ft·lb | 100 MMBTU |
| 1.000e+09 BTU | 7.782e+11 ft·lb | 1 billion BTU |
| 1.000e+10 BTU | 7.782e+12 ft·lb | 10 billion BTU |
| 1.000e+12 BTU | 7.782e+14 ft·lb | 1 quad fraction |
| 1.000e+15 BTU | 7.782e+17 ft·lb | 1 quad |
| 1.000e+18 BTU | 7.782e+20 ft·lb | 1000 quads |
1 BTU = 778.2 ft·lb. Memorize for instant estimates.
Use 778.2 as a quick mental multiplier.
Multiply result by 0.001285 to recover the original BTU value.
Sizes heating and cooling systems rated in BTU/hour for US buildings.
Certifies boiler output and efficiency ratings in BTU/hour.
Prices natural gas supply and usage in BTU and therms.
Calculates heating loads and heat loss in BTU for US properties.
Rates commercial refrigeration and ice-making capacity in BTU.
Specifies heat exchanger capacity and furnace output in BTU/hour.
The British Thermal Unit (BTU) is the traditional Imperial energy unit, defined as the heat required to raise 1 pound of water by 1°F. It equals 1,055.06 joules and has been used since the 19th century in heating, air conditioning, and gas billing.
BTU remains dominant in US HVAC: air conditioners and heaters are rated in BTU/hour. Natural gas is priced in therms (100,000 BTU) in the US. Furnaces are rated in BTU/hour output.
Interesting fact: A typical US home furnace is rated at 80,000–120,000 BTU/hour. One BTU is roughly the energy released by burning one kitchen match. The US natural gas pipeline system delivers about 25 quadrillion BTU (quads) per year.
The foot-pound (ft·lb) is an Imperial unit of energy equal to the work done when a force of one pound-force moves an object one foot, equaling 1.35582 joules. It has been used in British and American engineering since the 18th century.
Foot-pounds are standard in US mechanical engineering for torque specifications, engine output (often ft·lb of torque), and ballistic energy measurements. Rifle bullet energies are commonly quoted in foot-pounds in American publications.
Interesting fact: A typical 9mm pistol bullet has about 350 ft·lb of muzzle energy. The torque specification for tightening a car wheel bolt is typically 80–100 ft·lb. One horsepower equals 550 ft·lb per second.
Converting btu to foot-pound is common across energy, nutrition, engineering, and science. Different sectors use different energy units — joules in physics, kcal in nutrition, kWh in electricity, and BTU in HVAC — making accurate conversion essential for cross-disciplinary work and international comparisons.
Quick reference: 5 BTU = 3891 ft·lb and 10 BTU = 7782 ft·lb. Reverse: 1 ft·lb = 0.001285 BTU. Exact factor: 1 BTU = 778.2 ft·lb.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.