Foot-Pounds to Joules Converter
Convert foot-pounds of energy to joules — one foot-pound is 1.35582 J. Results update as you type; exact factors shown.
One foot-pound is 1.3558 joules — see the exact factor, not a rounded rule of thumb.
How the foot-pounds to joules converter works
Energy converts through the joule. A thermochemical calorie is exactly 4.184 J, so a food Calorie (kcal) is 4.184 kJ. A kilowatt-hour is exactly 3.6 MJ. A BTU is 1,055.056 J and a US therm is 100,000 BTU.
The UK is metric for most trade and science but keeps miles, pints, stone and mpg (with the imperial gallon) in daily life.
Common energy conversions
| From | To | Units |
|---|---|---|
| 1 ft·lb | 1.3558 J | foot-pound to joules |
| 5 ft·lb | 6.7791 J | foot-pounds to joules |
| 10 ft·lb | 13.5582 J | foot-pounds to joules |
| 25 ft·lb | 33.8954 J | foot-pounds to joules |
| 50 ft·lb | 67.7909 J | foot-pounds to joules |
| 100 ft·lb | 135.5818 J | foot-pounds to joules |
| 250 ft·lb | 338.9545 J | foot-pounds to joules |
| 500 ft·lb | 677.909 J | foot-pounds to joules |
| 1,000 ft·lb | 1,355.8179 J | foot-pounds to joules |
| 2,000 ft·lb | 2,711.6359 J | foot-pounds to joules |
| 2,600 ft·lb | 3,525.1267 J | foot-pounds to joules |
| 5,000 ft·lb | 6,779.0897 J | foot-pounds to joules |
Units in this converter and their exact factors
| Unit | Symbol | One unit in joules |
|---|---|---|
| joule | J | 1 joule |
| kilojoule | kJ | 1,000 joule |
| megajoule | MJ | 1,000,000 joule |
| calorie (thermochemical) | cal | 4.184 joule |
| kilocalorie (food Calorie) | kcal | 4,184 joule |
| watt-hour | Wh | 3,600 joule |
| kilowatt-hour | kWh | 3,600,000 joule |
| British thermal unit | BTU | 1,055.05585262 joule |
| therm (US) | thm | 105,505,585.262 joule |
| foot-pound | ft·lb | 1.3558179483 joule |
FAQFrequently asked questions about energy conversion
How many joules in a foot-pound?
1.35582 J.
Is this the same as pound-feet of torque?
No. Foot-pounds of energy and pound-feet of torque have the same dimensions and mean different things.
What is 2,600 ft·lb?
About 3,525 J — a typical rifle muzzle energy.
Where is it used?
US ballistics, mechanical work and older engineering texts.
What is 1 J in foot-pounds?
0.7376 ft·lb.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Physical Laboratory (NPL) — United Kingdom's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.