The joule is the SI derived unit of energy.
Joules to Foot-pounds Converter — J to ft-lb
Convert Joule (J) to Foot-pound (ft-lb) using the exact conversion factor (1 joule = 0.7375621493 foot-pound). See the formula, worked examples, conversion table, history, and common uses.
Joules to Foot-pounds converter
Converter
Engineering Converter
Convert common stress, force, torque, power, and energy units used in engineering.
Context values
Some unit families need one extra value for a physically accurate result.
Work from one pound-force over one foot.
Result = input x 1 / 1.355817948.
Energy units are compatible.
Reserved above the conversion cards and below the converter.
About Converting Joules to Foot-pounds
Joule and Foot-pound both measure a quantity used in structural or mechanical engineering — commonly stress, pressure, force, torque, power, or energy — where converting between the unit conventions used in different regions, industries, or equipment specifications is a routine part of design work. Joule is most often used for physics and engineering energy calculations.
Formula
foot-pounds = joules × 0.737562149277
This factor comes from each unit's defined relationship to the category's base unit: 1 joule equals 1 base unit, and 1 foot-pound equals 1.35581794833 base units, so dividing one by the other gives the direct joule-to-foot-pound factor of 0.737562149277.
Simple example
1 J × 0.7375621493 = 0.7375621493 ft-lb
1 joule = 0.7375621493 foot-pounds.
Real-world example
100 J × 0.7375621493 = 73.75621493 ft-lb
100 joules = 73.75621493 foot-pounds.
Conversion table
| Joule (J) | Foot-pound (ft-lb) |
|---|---|
| 1 J | 0.7375621493 ft-lb |
| 10 J | 7.375621493 ft-lb |
| 50 J | 36.87810746 ft-lb |
| 100 J | 73.75621493 ft-lb |
| 500 J | 368.7810746 ft-lb |
| 1,000 J | 737.5621493 ft-lb |
Reverse conversion: Foot-pound to Joule
0.7375621493 ft-lb × 1.355817948 = 1 J
0.7375621493 foot-pounds = 1 joules.
joules = foot-pounds × 1.35581794833
For a page dedicated to this direction, see Foot-pound to Joule.
Understanding the Joule
Joule (J) measures energy. The joule is the SI derived unit of energy, defined as the work done by one newton acting over one meter. It is classified as a SI derived unit.
Where it's used: Standard scientific and engineering energy unit worldwide
Uses of the Joule today
- Physics and engineering energy calculations
- Electrical energy in scientific contexts (though kWh is used for billing)
- Nutrition labeling in some countries (alongside or instead of calories)
History of the Joule
The joule is named after English physicist James Prescott Joule, whose experiments in the 1840s established the mechanical equivalent of heat — demonstrating that mechanical work and heat are interchangeable forms of energy, foundational to the first law of thermodynamics.
The unit itself was formally adopted as the SI derived unit of energy by international agreement as part of the broader SI system, defined coherently from the base units (kg, m, s) rather than as an independent physical standard.
Historical origin. Joule was not the invention of a single named person; it developed through the process described above.
Understanding the Foot-pound (ft-lb)
Work from one pound-force over one foot.
Joule — sources
- BIPM SI Brochure — Coherent derived units — Defines the joule as the SI unit of energy.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many foot-pounds are in 1 joule?
1 joule equals 0.7375621493 foot-pounds, using the exact defined conversion factor rather than an estimate.
How do I convert joule to foot-pound?
Multiply the joule value by 0.7375621493. The converter above does this instantly to whatever precision you set.
How do I convert foot-pound back to joule?
Use the reverse factor: 1 foot-pound equals 1.355817948 joules. You can also use the swap control in the converter above to flip the direction instantly.
What is a joule?
Joule (J) measures energy. The joule is the SI derived unit of energy, defined as the work done by one newton acting over one meter. It is classified as a SI derived unit.
What is a foot-pound?
Foot-pound (ft-lb) is a unit of engineering.
Is the joule to foot-pound conversion exact?
Yes. Both joule and foot-pound are defined by fixed standards rather than physical artifacts, so the factor of 0.7375621493 used above is exact to as many digits as you choose to display.
Where is the joule still used today?
Standard scientific and engineering energy unit worldwide
Why do engineering unit conventions vary so much by region and industry?
Pressure, force, and stress can be expressed in metric (pascal, newton), US customary (psi, pound-force), or older and industry-specific units (atmosphere, torr, kip) depending on the country, industry, and even the equipment manufacturer, which is why engineers routinely need to convert between them when working across specs from different sources.