Convert energy units — joules, kilowatt-hours, calories, BTU, electron volts and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 ft·lb | 1.35582e-06 kJ | |
| 0.01 ft·lb | 1.35582e-05 kJ | |
| 0.1 ft·lb | 0.000135582 kJ | |
| 1 ft·lb | 0.00135582 kJ | |
| 5 ft·lb | 0.0067791 kJ | |
| 10 ft·lb | 0.0135582 kJ | |
| 50 ft·lb | 0.067791 kJ | |
| 100 ft·lb | 0.135582 kJ | |
| 1000 ft·lb | 1.35582 kJ |
Formula: Kilojoule = Foot-Pound × 0.001356
Multiply any foot-pound value by 0.001356 to get kilojoule.
Reverse: Foot-Pound = Kilojoule × 737.6
Common foot-pound values — factor: 1 ft·lb = 0.001356 kJ
| Foot-Pound (ft·lb) | Kilojoule (kJ) | Context |
|---|---|---|
| 1 ft·lb | 0.001356 kJ | 1 ft·lb |
| 10 ft·lb | 0.01356 kJ | 10 ft·lb |
| 100 ft·lb | 0.1356 kJ | 100 ft·lb |
| 350 ft·lb | 0.4745 kJ | 9mm pistol |
| 550 ft·lb | 0.7457 kJ | 1 HP/s |
| 1,000 ft·lb | 1.356 kJ | Rifle bullet |
| 3,000 ft·lb | 4.067 kJ | High-power rifle |
| 1e+04 ft·lb | 13.56 kJ | 10 kft·lb |
| 1e+05 ft·lb | 135.6 kJ | 100 kft·lb |
| 1e+06 ft·lb | 1,356 kJ | 1 Mft·lb |
| 1e+07 ft·lb | 1.356e+04 kJ | 10 Mft·lb |
| 1.000e+09 ft·lb | 1.356e+06 kJ | 1 Gft·lb |
| 1.000e+12 ft·lb | 1.356e+09 kJ | 1 Tft·lb |
| 1.000e+15 ft·lb | 1.356e+12 kJ | 1 Pft·lb |
| 1.000e+18 ft·lb | 1.356e+15 kJ | 1 Eft·lb |
1 ft·lb = 0.001356 kJ. Memorize for instant estimates.
Use 0.0014 as a quick mental multiplier.
Multiply result by 737.6 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 kilojoule (kJ) equals 1,000 joules and is the practical energy unit for food, chemistry, and heating applications in metric countries. Food energy labels in Australia, Europe, and most of the world use kilojoules.
A dietary calorie (kcal) equals 4.184 kJ. A can of soda contains about 600 kJ. The specific heat of water (4.184 kJ/kg·°C) means heating 1 liter of water by 1°C requires 4.184 kJ.
Interesting fact: An average adult needs about 8,000-10,000 kJ (2,000-2,400 kcal) per day. Running a marathon burns approximately 12,500 kJ.
Converting foot-pound to kilojoule 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 = 0.006779 kJ and 10 ft·lb = 0.01356 kJ. Reverse: 1 kJ = 737.6 ft·lb. Exact factor: 1 ft·lb = 0.001356 kJ.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.