Foot-pound to Joule Converter
One Foot-pound equals 1.355817948 Joule (1 ft-lb = 1.355817948 J). Multiply a Foot-pound value by 1.355817948 to get the equivalent in Joule. Use the calculator above for instant results, or follow the formula, worked 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 Joule.
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-pound × 1.355817948 = 13.55817948 Joule.
- 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 Joule (1 ft-lb = 1.355817948 J). Foot-pound to Joule conversion comes up most often in US mechanical engineering and in firearm muzzle energy, typically when figures need restating for 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
15 Foot-pound equals 20.33726922 Joule.
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 Joule.
What is the formula for Foot-pound to Joule?
The formula is J = ft-lb × 1.355817948.
How many Joule are in 1 Foot-pound?
1 Foot-pound equals 1.355817948 Joule.
Can I convert Joule back to Foot-pound?
Yes. 1 Joule equals 0.7375621493 Foot-pound, 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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