Foot-pounds to Joules Converter
One Foot-pound equals 1.355817948 Joules (1 ft-lb = 1.355817948 J). Multiply a Foot-pound value by 1.355817948 to get the equivalent in Joules. Use the calculator above for your value, or check the examples and reference table below.
Formula
J = ft-lb × 1.355817948
Multiply the Foot-pound value by 1.355817948 to get the equivalent value in Joules.
Example Conversions
1 Foot-pound (ft-lb)
1.355817948 Joule (J)
5 Foot-pound (ft-lb)
6.779089741 Joule (J)
10 Foot-pound (ft-lb)
13.55817948 Joule (J)
25 Foot-pound (ft-lb)
33.89544871 Joule (J)
100 Foot-pound (ft-lb)
135.5817948 Joule (J)
Conversion Table
| Foot-pound (ft-lb) | Joule (J) |
|---|---|
| 0.1 | 0.1355817948 |
| 0.5 | 0.6779089741 |
| 1 | 1.355817948 |
| 2 | 2.711635897 |
| 5 | 6.779089741 |
| 10 | 13.55817948 |
| 25 | 33.89544871 |
| 50 | 67.79089742 |
| 100 | 135.5817948 |
| 250 | 338.9544871 |
| 500 | 677.9089741 |
| 1000 | 1355.817948 |
How to Convert Manually
Use these steps to convert Foot-pound values to Joule without the calculator.
- Write down the value in Foot-pound (ft-lb) that you want to convert.
- Multiply that value by 1.355817948.
- For example, 10 Foot-pounds × 1.355817948 = 13.55817948 Joules.
- Label the result as Joule (J).
Relative Size Comparison
This chart shows the visual difference in size between exactly one Foot-pound and one Joule.
About Foot-pound and Joule
The foot-pound is about 1.3558 joules, the work of one pound-force through one foot. US mechanical engineering and firearm muzzle energy use foot-pounds. The joule is the SI derived unit of energy, the work done by a force of one newton over one meter. Physics, chemistry, and food labeling outside the US build on it. One Foot-pound equals 1.355817948 Joules (1 ft-lb = 1.355817948 J). Foot-pound is used in US mechanical engineering and in firearm muzzle energy. Joule is used in physics and engineering calculations.
Precision and Rounding:Energy factors mix exact definitions (1 kWh = 3,600,000 J; 1 cal = 4.184 J thermochemical) with measured conventions (1 BTU ≈ 1,055.056 J). Nutrition and utility bills round to whole units; engineering heat calculations should keep the full factor until the final step.
Conversion factors per NIST Special Publication 811 and the BIPM SI Brochure (9th edition) (reference).
Worked Example
15Foot-pounds equals20.33726922Joules.
15 ft-lb × 1.355817948 = 20.33726922 J
FAQ
How do I convert Foot-pound to Joule?
Multiply the Foot-pound value by 1.355817948 to get the equivalent value in Joules.
What is the formula for Foot-pound to Joule?
The formula is J = ft-lb × 1.355817948.
How many Joules are in 1 Foot-pound?
1 Foot-pound equals 1.355817948 Joules.
Can I convert Joule back to Foot-pound?
Yes. 1 Joule equals 0.7375621493 Foot-pounds, and the related converter can reverse the calculation.
What are common names for Foot-pound and Joule?
Foot-pound is shown as ft-lb and may also be searched as foot-pound, foot pound, ft·lb. Joule is shown as J and may also be searched as joule, joules.
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