Foot Pounds of Energy Calculator

What Are Foot-Pounds of Energy?

Foot-pounds (ft·lbf) measure kinetic energy in the imperial system. One foot-pound is the energy needed to lift one pound one foot against gravity. In ballistics, machinery, and sports science, ft·lbf is a common way to express how much energy a moving object carries.

Kinetic Energy Formula

$$KE = \frac{1}{2}mv^2$$

Mass $m$ is in kilograms and velocity $v$ is in meters per second for SI joules. To convert joules to foot-pounds, divide by 1.35582. Example: a 1 kg object at 10 m/s has $KE = 0.5 \times 1 \times 10^2 = 50$ J, which equals about 36.9 ft·lbf.

When to Use ft·lbf vs Joules

Joules are standard in physics and engineering worldwide. Foot-pounds appear in US shooting catalogs, automotive specs, and legacy mechanical drawings. This calculator converts both from the same mass and speed inputs.

Related tools: Bullet Energy Calculator and G-Force Calculator.

Frequently Asked Questions

How do I convert joules to foot-pounds?

Divide joules by 1.35582. For example, 50 J ≈ 36.9 ft·lbf. This calculator performs the conversion automatically.

Does kinetic energy depend on direction?

No. Kinetic energy depends only on mass and speed (magnitude of velocity), not the direction of motion.

Can I use pounds and feet per second?

Yes. Select pounds for mass and feet per second for velocity. The tool converts to SI units before applying KE = ½mv².

Is ft·lbf the same as foot-pounds of torque?

They share the same unit symbol but measure different quantities. Here we compute energy (work), not rotational torque.

What if velocity is zero?

Kinetic energy is zero when speed is zero, regardless of mass. The object has no motion energy.

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Foot Pounds Of Energy Calculator

What Are Foot-Pounds of Energy?

Kinetic Energy Formula

When to Use ft·lbf vs Joules

Frequently Asked Questions

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