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Energy
Foot-pounds to Joules
Convert foot-pounds (ft·lb) to joules (J). Type a value below to see the result update instantly. Reference table and formula included.
Calculator
1 ft·lb = 1.3558 J
Foot-pounds to Joules Conversion Table
Common values, ready to copy:
| foot-pounds | joules |
|---|---|
| 1 ft·lb | 1.3558 J |
| 2 ft·lb | 2.7116 J |
| 5 ft·lb | 6.7791 J |
| 10 ft·lb | 13.5582 J |
| 25 ft·lb | 33.8955 J |
| 50 ft·lb | 67.791 J |
| 100 ft·lb | 135.58 J |
| 1,000 ft·lb | 1355.82 J |
Formula
joules = foot-pounds × 1.35582
Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.
About Foot-pounds and Joules
Foot-pounds (ft·lb): The work done lifting one pound through one foot against gravity; 1 ft·lb = 1.35582 J. Common uses: Torque specifications in US automotive contexts (lug nuts, bolt torque), and some US engineering work.
Joules (J): The SI unit of energy; named for James Prescott Joule, whose 19th-century experiments established the equivalence of mechanical work and heat. Common uses: Physics calculations, food calorie labeling in metric countries (kilojoules), battery capacity, and chemistry.
How the conversion works
Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.
The exact relationship is joules = foot-pounds × 1.35582, which the calculator at the top of this page applies in both directions. Type into either field and the other updates immediately.
When this conversion matters
Converting between foot-pounds and joules comes up wherever energy measurements move between systems — from one country's conventions to another's, from a scientific reference to a practical specification, or from one industry's working unit to another's. The calculator and reference table above cover the everyday range; for unusual values you can type any number into either field.