Lever Calculator — Mechanical Advantage & Force
A lever multiplies force: enter any three of the four variables — effort force, effort arm, load force, and load arm — and the calculator solves for the missing one using the principle of moments (F₁ × d₁ = F₂ × d₂). Works for all three lever classes.
N
m
N
m
Lever class
Ratio of load force to effort force (> 1 = force multiplication)
Principle of moments
Substituted values
Moment (torque)
Mechanical Advantage
- 1
Effort moment = F₁ × d₁
50 N × 2 m = 100Both sides of a balanced lever have equal torques: F₁d₁ = F₂d₂. - 2
Mechanical Advantage = d₁ ÷ d₂
2 ÷ 0.5 = 4
How does this calculator work?
A lever obeys F₁ × d₁ = F₂ × d₂. Enter any three values and the fourth is solved instantly. Mechanical advantage = d₁ / d₂: a 2 m effort arm vs a 0.5 m load arm gives MA = 4, meaning 100 N of effort can lift a 400 N load.
Formula
How this is calculated
A lever is a rigid beam pivoting on a fulcrum. The principle of moments states that when the lever is balanced, the torques on either side are equal: F₁ × d₁ = F₂ × d₂, where F₁ is the effort force (applied by the user), d₁ is the effort arm (distance from the effort to the fulcrum), F₂ is the load force (resistance being overcome), and d₂ is the load arm (distance from the fulcrum to the load).
The mechanical advantage (MA = d₁/d₂) tells you how much the lever multiplies your effort. MA > 1 means you apply less force than the load — useful for lifting heavy objects. MA < 1 means you trade force for speed or range of motion. The three lever classes differ only in the relative position of the fulcrum, effort and load: Class 1 (fulcrum in the middle, e.g. seesaw, crowbar), Class 2 (load in the middle, e.g. wheelbarrow, nutcracker), Class 3 (effort in the middle, e.g. tweezers, fishing rod).
This calculator assumes an ideal, massless, rigid lever (no friction, no beam weight). Real levers lose some efficiency to friction at the fulcrum and beam deflection, so actual force requirements are slightly higher than the theoretical result.
Frequently asked questions
Mechanical advantage (MA) is the ratio of output force to input force (or equivalently the effort arm to the load arm). MA = 3 means a 100 N push produces 300 N of force on the load. It is how a lever lets you lift heavy objects with little effort.
Class 1 has the fulcrum between effort and load (seesaw, scissors). Class 2 has the load between the fulcrum and effort, always giving MA > 1 (wheelbarrow, bottle opener). Class 3 has the effort between the fulcrum and load, always giving MA < 1 — trading force for speed (tweezers, fly fishing rod).
Divide the force in newtons by g ≈ 9.81 m/s². So 100 N ÷ 9.81 ≈ 10.2 kg. The calculator displays the equivalent mass of the load force for convenience.
Also known as
TG we-Calculate Editorial Team. (2026). Lever Calculator — Mechanical Advantage & Force [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/lever-calculator
TG we-Calculate Editorial Team. "Lever Calculator — Mechanical Advantage & Force." TG we-Calculate. 2026. https://we-calculate.com/calculator/lever-calculator.
TG we-Calculate Editorial Team, "Lever Calculator — Mechanical Advantage & Force," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/lever-calculator
@misc{wecalculate_lever_calculator, title = {Lever Calculator — Mechanical Advantage & Force}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/lever-calculator}}, year = {2026}, note = {TG we-Calculate} }
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