Foot Pounds to Kilojoules
Type a value in either box to convert between foot pounds and kilojoules. The factor is 0.00135582.
| Foot Pounds | Kilojoules |
|---|---|
| 1 ft·lb | 0.001356 kJ |
| 2 ft·lb | 0.002712 kJ |
| 3 ft·lb | 0.004067 kJ |
| 5 ft·lb | 0.006779 kJ |
| 10 ft·lb | 0.013558 kJ |
| 25 ft·lb | 0.033895 kJ |
| 50 ft·lb | 0.067791 kJ |
| 100 ft·lb | 0.135582 kJ |
How to use
- Enter a value in the Foot Pounds field.
- The Kilojoules figure appears immediately — no button to press.
- Typing in the Kilojoules field converts back to Foot Pounds the same way.
- Use the reference table for the values that come up most often.
Foot Pounds to Kilojoules formula
To convert foot pounds to kilojoules, multiply by 0.00135581795.
kJ = ft·lb × 0.00135581795
Why this factor: the foot-pound and the kilojoule are both defined against the joule, so dividing one definition by the other gives 0.00135581795 directly. Both definitions are set out in full below.
To go the other way, divide by 0.00135581795 — or use the Kilojoules to Foot Pounds converter, which is the same calculation reversed.
Worked example
Given 2000 ft·lb, multiplying by 0.00135581795 yields 2.711636 kJ.
2000 ft·lb × 0.00135581795 = 2.711636 kJ
The converter above does this for any value you type, in either direction.
What is a foot-pound?
A foot-pound is the work done by one pound-force acting through one foot.
Definition: About 1.3558179 joules.
Where it is used: US mechanical work and torque figures, fastener specifications, and firearm muzzle energy.
Worth knowing: As a torque unit it is properly 'pound-foot' (lbf·ft); as an energy unit it is 'foot-pound'. The numbers coincide but the quantities differ.
What is a kilojoule?
A kilojoule is 1,000 joules, the metric unit of food energy.
Definition: Exactly 1,000 joules.
Where it is used: Nutrition labels in Europe and Australia, and heating and cooling loads.
Foot Pounds vs Kilojoules
The foot-pound is a US customary unit while the kilojoule is a metric unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many kilojoules are in a foot-pound?
One foot-pound equals 0.00135581795 kilojoules.
What is the formula to convert foot pounds to kilojoules?
Multiply the number of foot pounds by 0.00135581795. To reverse it, divide by 0.00135581795 instead.
How do I convert kilojoules back to foot pounds?
Divide by 0.00135581795, which is the same as multiplying by 737.562149.
How many kilojoules are in 10 foot pounds?
10 ft·lb works out to 0.013558 kJ.
Is there anything to watch out for with foot pounds?
As a torque unit it is properly 'pound-foot' (lbf·ft); as an energy unit it is 'foot-pound'. The numbers coincide but the quantities differ.
How is the foot-pound defined?
About 1.3558179 joules.