CalcaTools

Energy Foot-Pounds Calculator | Work from force & distance

SPONSORED
Calculate mechanical work in foot-pounds from force and distance, then convert to joules and kilojoules with the exact factor. The formula Work = Force × Distance is applied with each step shown — essential for physics homework, torque work and engineering estimates.

Last updated: July 2026 · Free · No sign-up required

kg
m/s²
SPONSORED
Results

Enter values above and click Calculate to see your result instantly.

About the Energy Foot Pounds Calculator

Behind the inputs above sits one rule: Work (ft-lb) = Force (lb) x Distance (ft); 1 ft-lb = 1.35582 J. The tool evaluates it instantly with the values you enter.

If you are new to foot pounds calculator, start with the worked example in the methodology section below — it walks the formula end-to-end with real numbers — then use the quick-reference table for common scenarios.

From our guides

Quick reference

Convert foot-poundsEquals
1 ft·lb1.35582 joules
1 ft·lb0.001285 BTU
1 joule0.73756 ft·lb
1 ft·lb/s1.35582 watts

info Energy Foot Pounds Calculator

Free math calculator — enter your numbers and get an instant, accurate result.

info Private by design

Everything runs locally in your browser. No uploads, no accounts, no tracking.

info Works everywhere

Fully responsive and mobile-friendly — calculate on any device, any time.

info Educational

Includes the formula and step-by-step explanation so you understand the math, not just the answer.

Interpretation guide

QuantityFormula (US units)
Work (energy)W = force (lb) x distance (ft)
TorqueT = force (lb) x lever arm (ft)
Powerft·lb per second or minute

lightbulb Worked example

Let's say you are using the Energy Foot Pounds Calculator. Calculates foot pounds using Work (ft-lb) = Force (lb) x Distance (ft), instantly in your browser. Enter the values that match your situation into the input fields and press calculate — using realistic numbers makes the result directly useful for you.

Result: The calculator instantly applies the formula Work (ft-lb) = Force (lb) x Distance (ft); 1 ft-lb = 1.35582 J and returns the result with appropriate precision.

What this means: Read the result in the context of what you are measuring. The step-by-step breakdown lets you confirm the math and understand which input most affects the outcome.

Formula & methodology

Formula: Work (ft-lb) = Force (lb) x Distance (ft); 1 ft-lb = 1.35582 J

The Energy Foot Pounds Calculator is built on a well-established calculation method. It uses the formula Work (ft-lb) = Force (lb) x Distance (ft); 1 ft-lb = 1.35582 J to turn your inputs into a reliable result. Calculates foot pounds using Work (ft-lb) = Force (lb) x Distance (ft), instantly in your browser. The steps are shown on the page so you can follow the reasoning from input to output.

How foot-pounds of energy are calculated

A foot-pound of work is the energy used to move a 1-pound force through 1 foot. Multiply the force by the distance moved in the direction of the force.

Example

Lifting a 50-lb weight 4 feet: W = 50 x 4 = 200 ft·lb. In SI that is 200 x 1.35582 = 271.2 joules.

Note that foot-pound (energy/torque) and pound-foot are dimensionally the same unit but describe different physics — energy when force acts over a distance, torque when force acts on a lever arm. Always confirm which one a spec means.

Authoritative source: Wolfram MathWorld

Frequently asked questions

What is a foot-pound?
A foot-pound (ft·lb) is a unit of work or energy in the US customary system — the energy needed to move a force of one pound through a distance of one foot. It equals about 1.356 joules. The same unit name is also used for torque, where it means a pound of force on a one-foot lever arm.
How do you calculate foot-pounds of energy?
Multiply the force in pounds by the distance moved in feet, in the direction of the force: work = force x distance. Lifting a 25-lb box 6 feet does 25 x 6 = 150 ft·lb of work. Only motion along the force direction counts.
How do you convert foot-pounds to joules?
Multiply foot-pounds by 1.35582 to get joules: 100 ft·lb = 135.6 J. To go the other way, multiply joules by 0.73756 to get foot-pounds. The factor comes from combining the pound-force and foot definitions with the SI metre and newton — 1 ft·lb = 1.35582 J exactly, and the converter applies it in both directions.
Is a foot-pound the same as a pound-foot?
They share the same dimensions but describe different things by convention. 'Foot-pound' (ft·lb) usually denotes energy or work — force acting through a distance. 'Pound-foot' (lb·ft) usually denotes torque — force acting on a lever arm. Many sources use them loosely, so always check the context.
What is foot-pounds used for?
Foot-pounds measure mechanical work and energy in US engineering — lifting loads, the muzzle energy of bullets, the output of engines, and the tightening torque of bolts (as pound-feet). It is the customary counterpart to the joule, and conversions between the two are common in technical work.
How is foot-pound energy calculated from weight and velocity?
E(ft·lb) = weight(grains) × velocity(fps)² ÷ 450,240. A 55-grain projectile at 3,100 fps carries 55 × 3,100² ÷ 450,240 ≈ 1,174 ft·lb. The divisor bundles the grain-to-slug mass conversion with the ½ in ½mv² — enter the two numbers and the calculator handles it.
When would I use foot-pounds instead of joules?
Foot-pounds are the customary unit in US engineering, ballistics (muzzle energy) and work problems in imperial-unit textbooks. The tool also gives joules via the exact factor 1 ft-lb = 1.35582 J, so a 500 ft-lb result reads about 678 J. If your course uses SI units, read the joule column.
Is a foot-pound of work the same as a pound-foot of torque?
They share dimensions but describe different things: work (ft-lb) = force × distance moved in the force's direction, while torque (lb-ft) = force × lever arm, a twisting moment. The tool computes work/energy — e.g. lifting 50 lb through 10 ft = 500 ft-lb. Do not use it for bolt torque specs.
Does the formula still work if the force is not constant?
The basic equation assumes constant force along a straight-line displacement. For varying force — a stretching spring, for instance — the true work is the integral of force over distance, which this tool does not compute. It is exact for steady pushes, lifts and drags; for variable resistance, treat the result as an average-force approximation.
Can I enter metric values like newtons and metres?
The inputs expect pounds and feet, matching the unit's definition. If you have newtons and metres, compute joules directly (1 J = 1 N·m) and convert with 1 ft-lb = 1.35582 J — or convert first (1 lb ≈ 4.448 N, 1 ft = 0.3048 m). Mixing units without converting is the classic error, so the tool keeps to one system.

Explore the full unit converter toolkit

Every CalcaTools converter — length, volume, weight, time and date, number notation, science and energy, plus file, text and colour utilities — each with instant results and worked explanations.

Length & distance

Volume, weight & capacity

Time & date

Numbers & notation

Science & energy

Files, text & color