Lever Calculator

About this calculator

A lever balances around its fulcrum according to the principle of moments — first formalized by Archimedes — where the torque applied by the effort force equals the torque needed to support the load: Effort force × Effort arm = Load force × Load arm. Rearranging gives the effort force required for a given load, while the ratio of the two arm lengths, Mechanical advantage = Effort arm / Load arm, tells you how much the lever multiplies (or reduces) force.

This exact torque-balance relationship governs everything from a crowbar prying up a nail to a see-saw, wheelbarrow, or bottle opener — first-class, second-class, and third-class levers all follow the same equation, differing only in where the fulcrum, effort, and load sit relative to each other.

Mechanical engineering students learning simple machines, tool designers positioning a fulcrum for maximum leverage, and DIYers figuring out whether a given pry bar or lever arrangement can move a heavy object all use this relationship to size the force and arm lengths needed for the job.