Convert energy units — joules, kilowatt-hours, calories, BTU, electron volts and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 ft·lb | 0.00135582 J | |
| 0.01 ft·lb | 0.0135582 J | |
| 0.1 ft·lb | 0.135582 J | |
| 1 ft·lb | 1.35582 J | |
| 5 ft·lb | 6.7791 J | |
| 10 ft·lb | 13.5582 J | |
| 50 ft·lb | 67.791 J | |
| 100 ft·lb | 135.582 J | |
| 1000 ft·lb | 1355.82 J |
Formula: Joule = Foot-Pound × 1.356
Multiply any foot-pound value by 1.356 to get joule.
Reverse: Foot-Pound = Joule × 0.7376
Common foot-pound values — factor: 1 ft·lb = 1.356 J
| Foot-Pound (ft·lb) | Joule (J) | Context |
|---|---|---|
| 1 ft·lb | 1.356 J | 1 ft·lb |
| 10 ft·lb | 13.56 J | 10 ft·lb |
| 100 ft·lb | 135.6 J | 100 ft·lb |
| 350 ft·lb | 474.5 J | 9mm pistol |
| 550 ft·lb | 745.7 J | 1 HP/s |
| 1,000 ft·lb | 1,356 J | Rifle bullet |
| 3,000 ft·lb | 4,067 J | High-power rifle |
| 1e+04 ft·lb | 1.356e+04 J | 10 kft·lb |
| 1e+05 ft·lb | 1.356e+05 J | 100 kft·lb |
| 1e+06 ft·lb | 1.356e+06 J | 1 Mft·lb |
| 1e+07 ft·lb | 1.356e+07 J | 10 Mft·lb |
| 1.000e+09 ft·lb | 1.356e+09 J | 1 Gft·lb |
| 1.000e+12 ft·lb | 1.356e+12 J | 1 Tft·lb |
| 1.000e+15 ft·lb | 1.356e+15 J | 1 Pft·lb |
| 1.000e+18 ft·lb | 1.356e+18 J | 1 Eft·lb |
ft·lb × 1.356 = J. Round to × 1.36.
One foot-pound is about 1.36 joules.
J ÷ 1.356 = ft·lb.
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 joule is the SI derived unit of energy, work, and heat, defined as the energy transferred when a force of one newton moves an object one meter. It was named after James Prescott Joule, the English physicist who established the mechanical equivalent of heat in the 1840s.
The joule is universal in physics and engineering: kinetic energy (½mv²), potential energy (mgh), electrical energy (VIt), and heat are all measured in joules. One joule is the energy needed to lift a 100g apple one meter against gravity.
Interesting fact: The human heart expends about 1 joule of energy with each beat. A 60-watt light bulb uses 60 joules every second. The entire energy released by a 1-megaton nuclear weapon equals about 4.18 × 10¹⁵ joules.
Converting foot-pound to joule 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 = 6.779 J and 10 ft·lb = 13.56 J. Reverse: 1 J = 0.7376 ft·lb. Exact factor: 1 ft·lb = 1.356 J.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.