How many joules are in one foot-pound?

1 foot-pound (ft·lbf) equals exactly 1.35581794833 joules. This is defined by the international foot (0.3048 m) and the pound-force (4.44822 N).

How do I convert foot-pounds to joules?

Multiply the ft·lbf value by 1.35582. For example, 100 ft·lbf × 1.35582 = 135.582 J. This tool does the calculation automatically in real time.

What is a foot-pound (ft·lbf)?

A foot-pound is an imperial unit of energy or work. It equals the energy transferred when a one-pound force moves an object one foot. It is used in the US for engine torque, firearm muzzle energy, and structural impact values.

Is foot-pound the same as pound-foot?

"Foot-pound" (ft·lbf) and "pound-foot" (lb·ft) describe the same quantity. "Foot-pound" is the traditional term for energy and work; "pound-foot" is often used for torque in automotive contexts, but the magnitude is identical.

How many foot-pounds equal one joule?

1 joule equals 0.737562 foot-pounds (ft·lbf). To convert joules to ft·lbf, multiply by 0.737562.

Where is the foot-pound unit commonly used?

Foot-pounds appear in US automotive specs (engine torque), firearms (muzzle energy), archery (draw energy), and mechanical engineering. Most other countries use joules or newton-meters.

Foot Pounds to Joules Converter

Name: Foot Pounds to Joules Converter
Availability: InStock
Author: Nham Vu

Enter foot-pounds (ft·lbf) or joules for instant bidirectional energy conversion with a reference table of common values.

Foot-Pounds ↔ Joules Converter

Foot-Pounds (ft·lbf)

ft·lbf

⇅

Joules (J)

Kilojoules (kJ)

1 ft·lbf = 1.35581795 J — 1 J = 0.737562 ft·lbf

Quick Reference Table

Common ft·lbf values in joules (1 ft·lbf = 1.35582 J)

ft·lbf	Joules (J)	kJ

1 ft·lbf = 1.35581794833 J — international foot and pound-force definition

Common real-world references

9mm pistol muzzle energy: ~370 ft·lbf (500 J)
.308 rifle muzzle energy: ~2,650 ft·lbf (3,590 J)
Typical car engine torque: 150–400 ft·lbf (203–542 J equivalent)
Recurve bow draw energy: ~30–60 ft·lbf (41–81 J)
One food calorie (kcal): ~3,085 ft·lbf (4,184 J)

Summary

Enter foot-pounds (ft·lbf) or joules for instant bidirectional energy conversion with a reference table of common values.

How it works

Enter a foot-pound value in the ft·lbf field to see the joule (and kJ) equivalent instantly.
Enter a value in the Joules field to reverse-convert back to foot-pounds.
The kJ field also accepts input and converts in all directions.
All three fields update in real time — no button click needed.
Click any row in the reference table to load that value into the converter.

Use cases

Convert engine torque specs from ft·lbf to newton-meters (J equivalent) for metric markets.
Translate firearm muzzle energy figures between imperial ft·lbf and SI joules.
Convert bow or crossbow draw energy ratings reported in foot-pounds to joules.
Verify impact energy specs in structural or mechanical engineering calculations.
Translate US physics textbook answers from ft·lbf into SI joules for international coursework.

Frequently Asked Questions

Last updated: 2026-07-22 · Reviewed by Nham Vu