Convert energy units — joules, kilowatt-hours, calories, BTU, electron volts and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 ft·lb | 1.28506e-06 BTU | |
| 0.01 ft·lb | 1.28506e-05 BTU | |
| 0.1 ft·lb | 0.000128506 BTU | |
| 1 ft·lb | 0.00128506 BTU | |
| 5 ft·lb | 0.00642532 BTU | |
| 10 ft·lb | 0.0128506 BTU | |
| 50 ft·lb | 0.0642532 BTU | |
| 100 ft·lb | 0.128506 BTU | |
| 1000 ft·lb | 1.28506 BTU |
Formula: BTU = Foot-Pound × 0.001285
Multiply any foot-pound value by 0.001285 to get btu.
Reverse: Foot-Pound = BTU × 778.2
Common foot-pound values — factor: 1 ft·lb = 0.001285 BTU
| Foot-Pound (ft·lb) | BTU (BTU) | Context |
|---|---|---|
| 1 ft·lb | 0.001285 BTU | 1 ft·lb |
| 10 ft·lb | 0.01285 BTU | 10 ft·lb |
| 100 ft·lb | 0.1285 BTU | 100 ft·lb |
| 350 ft·lb | 0.4498 BTU | 9mm pistol |
| 550 ft·lb | 0.7068 BTU | 1 HP/s |
| 1,000 ft·lb | 1.285 BTU | Rifle bullet |
| 3,000 ft·lb | 3.855 BTU | High-power rifle |
| 1e+04 ft·lb | 12.85 BTU | 10 kft·lb |
| 1e+05 ft·lb | 128.5 BTU | 100 kft·lb |
| 1e+06 ft·lb | 1,285 BTU | 1 Mft·lb |
| 1e+07 ft·lb | 1.285e+04 BTU | 10 Mft·lb |
| 1.000e+09 ft·lb | 1.285e+06 BTU | 1 Gft·lb |
| 1.000e+12 ft·lb | 1.285e+09 BTU | 1 Tft·lb |
| 1.000e+15 ft·lb | 1.285e+12 BTU | 1 Pft·lb |
| 1.000e+18 ft·lb | 1.285e+15 BTU | 1 Eft·lb |
1 ft·lb = 0.001285 BTU. Memorize for instant estimates.
Use 0.0013 as a quick mental multiplier.
Multiply result by 778.2 to recover the original ft·lb value.
Torques bolts and fasteners to specified ft·lb values using a torque wrench.
Rates firearm muzzle energy in ft·lb for US ammunition comparisons.
Calculates impact energy absorption in ft·lb for US building codes.
Measures and compares engine torque output in ft·lb on a dyno.
Specifies fall arrest and impact energy in ft·lb for OSHA compliance.
Evaluates hunting cartridge terminal energy in ft·lb for ethical dispatch.
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.
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.
Converting foot-pound to btu 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 ft·lb = 0.006425 BTU and 10 ft·lb = 0.01285 BTU. Reverse: 1 BTU = 778.2 ft·lb. Exact factor: 1 ft·lb = 0.001285 BTU.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.