Foot-pounds to Joules Converter
Enter the energy in foot-pounds below to convert it to joules.
Convert Foot-pounds to Joules
Enter a value in foot-pounds (ft·lbf) to convert to joules (J).
Foot-pound to Joule Conversion Table
Table showing various foot-pound measurements converted to joules. Click any preset value or arrow to load it into the converter.
| Foot-pounds (ft·lbf) | Joules (J) |
|---|---|
| 1 ft·lbf | 1.3558179 J |
| 2 ft·lbf | 2.7116359 J |
| 5 ft·lbf | 6.7790897 J |
| 10 ft·lbf | 13.5581795 J |
| 15 ft·lbf | 20.3372692 J |
| 20 ft·lbf | 27.116359 J |
| 25 ft·lbf | 33.8954487 J |
| 30 ft·lbf | 40.6745384 J |
| 50 ft·lbf | 67.7908974 J |
| 75 ft·lbf | 101.6863461 J |
How to Convert Foot-pounds to Joules
To convert foot-pounds to joules, multiply the energy by the following conversion ratio: 1.3558179 joules/foot-pound.
Since one foot-pound is equal to 1.3558179 joules, you can use this simple formula to convert:
The energy in joules is equal to the energy in foot-pounds multiplied by 1.3558179.
For example, here's how to convert 100 foot-pounds to joules using the formula above.
How Many Joules Are in a Foot-pound?
There are 1.3558179 joules in a foot-pound, which is why we use this value in the formula above.
Our foot-pound to joule calculator automatically converts your energy measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Foot-pounds and joules are both units used to measure energy. Keep reading to learn more about each unit.
What Is a Foot-pound?
A foot-pound is a unit of energy equal to 1.3558179 joules (J), the base unit for energy. Mechanical work unit equal to 1.355818 Joules. [1]
The foot-pound is classified as a US customary and imperial unit of energy. Foot-pounds can be abbreviated as ft·lbf; for example, 1 foot-pound can be written as 1 ft·lbf.
When working with foot-pounds (ft·lbf) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.
In practice, foot-pounds (ft·lbf) are widely used across standard energy applications within US customary and imperial workflows, engineering documentation, and technical data sheets.
What Is a Joule?
Coherent SI unit of energy and work (1 W·s = 1 N·m). It serves as a primary reference unit for measuring energy across scientific and practical applications. [2]
The joule is classified as an International System of Units (SI) unit of energy. Joules can be abbreviated as J; for example, 1 joule can be written as 1 J.
As the primary coherent reference unit for energy in this category, all other energy units are mathematically anchored to the joule (J).
In practice, joules (J) are widely used across standard energy applications within International System of Units (SI) workflows, engineering documentation, and technical data sheets.
When converting energy between foot-pounds (ft·lbf) and joules (J), keep full floating-point precision (1 ft·lbf = 1.3558179 J; 1 J = 0.7375621 ft·lbf) during intermediate calculations and round only the final joule figure to match your instrument tolerance.
More Foot-pound & Joule Conversions
Need to calculate in the opposite direction? Use our joules to foot-pounds converter (J to ft·lbf) to switch your starting unit immediately. You can also explore related tools such as converting calories to joules, converting kilojoules to joules, or converting joules to calories.
Convert from Foot-pounds
Frequently Asked Questions
References
- [1]NIST CODATA StandardNIST CODATA (CODATA Energy & Thermodynamic Constants)·Energy Metrology Standard — Foot-pounds (ft·lbf) to Joules (J)
- [2]NIST SP 811 SpecificationNIST SP 811 (NIST SP 811 App. B.9 (Energy, Work & Heat))·Unit Specifications: Foot-pound (ft·lbf) (ft·lbf) & Joule (J)
- [3]BIPM ReferenceBIPM (Derived SI Unit: Joule (J))·Conversion Factors & Mathematical Basis (ft·lbf to J)