Foot-pounds to Joules
Type a value in Foot-pounds and get the result in Joules, calculated exactly.
100 Foot-pounds ≈ 135.5817948 Joules
Precision
Exact factorRounded for display to about 10 significant digits.
Slide rule
Drag to scrub · arrow keys step · Shift × 10Paper tape
ConvertThemAll
- Your conversions print here.
0 lines · kept on this device only
Formula
J = ft·lbf × 1.35581794833
To convert Foot-pounds to Joules, multiply the value by 1.35581794833.
Worked examples
- 1 ft·lbf × 1.35581794833 ≈ 1.355817948 J
- 100 ft·lbf × 1.35581794833 ≈ 135.5817948 J
- 50 ft·lbf × 1.35581794833 ≈ 67.79089742 J
This factor is exact by definition.
Conversion table
| Foot-pounds (ft·lbf) | Joules (J) |
|---|---|
| 1 | ≈ 1.355818 |
| 2 | ≈ 2.711636 |
| 3 | ≈ 4.067454 |
| 4 | ≈ 5.423272 |
| 5 | ≈ 6.77909 |
| 6 | ≈ 8.134908 |
| 7 | ≈ 9.490726 |
| 8 | ≈ 10.84654 |
| 9 | ≈ 12.20236 |
| 10 | ≈ 13.55818 |
| 15 | ≈ 20.33727 |
| 20 | ≈ 27.11636 |
| 25 | ≈ 33.89545 |
| 30 | ≈ 40.67454 |
| 40 | ≈ 54.23272 |
| 50 | ≈ 67.7909 |
| 60 | ≈ 81.34908 |
| 70 | ≈ 94.90726 |
| 75 | ≈ 101.6863 |
| 80 | ≈ 108.4654 |
| 90 | ≈ 122.0236 |
| 100 | ≈ 135.5818 |
Values marked ≈ are rounded; the rest are exact.
Reverse table: Joules to Foot-pounds
| Joules (J) | Foot-pounds (ft·lbf) |
|---|---|
| 1 | ≈ 0.7375621 |
| 2 | ≈ 1.475124 |
| 3 | ≈ 2.212686 |
| 4 | ≈ 2.950249 |
| 5 | ≈ 3.687811 |
| 6 | ≈ 4.425373 |
| 7 | ≈ 5.162935 |
| 8 | ≈ 5.900497 |
| 9 | ≈ 6.638059 |
| 10 | ≈ 7.375621 |
| 15 | ≈ 11.06343 |
| 20 | ≈ 14.75124 |
| 25 | ≈ 18.43905 |
| 30 | ≈ 22.12686 |
| 40 | ≈ 29.50249 |
| 50 | ≈ 36.87811 |
| 60 | ≈ 44.25373 |
| 70 | ≈ 51.62935 |
| 75 | ≈ 55.31716 |
| 80 | ≈ 59.00497 |
| 90 | ≈ 66.38059 |
| 100 | ≈ 73.75621 |
Unit definitions
- Foot-pounds ft·lbf
- One pound-force over one foot: exactly 1.3558179483314004 joules.
- Joules J
- The SI unit of energy: one newton acting over one metre, or one watt for one second.
Questions people ask
Foot-pounds to Joules: what is the conversion factor?
One ft·lbf is ≈ 1.355817948 J.
How do I convert Foot-pounds to Joules?
Use the formula above. For example, 100 ft·lbf = ≈ 135.5817948 J.
Is the conversion exact?
Yes. Both units have exact definitions, so the factor is exact; a result is only rounded when its decimals never end.
Factors checked 19 October 2026.