By Zencalcy Editorial TeamLast reviewed About us
A lever trades force for distance around a fulcrum. The effort times its distance from the pivot must equal the load times its distance, so moving the fulcrum closer to the load reduces the effort needed.
Balance effort and load on a lever.
F_e d_e = F_l d_l
F_e is effort, d_e the effort arm, F_l the load and d_l the load arm. Arm lengths are measured perpendicular to the forces from the fulcrum.
| Symbol | Meaning |
|---|---|
| F_e, F_l | Effort and load forces, in newtons. |
| d_e, d_l | Effort and load arm lengths, in metres. |
The effort needed is 500 × 1 / 2 = 250 N. The mechanical advantage is 2, and the effort moves twice as far as the load.
Continue with the Mechanical Advantage Calculator, Pulley System Calculator, or the Screw Mechanical Advantage Calculator — or browse more simple machines tools and all physics calculators.
Class 1 has the fulcrum between effort and load; class 2 has the load in the middle; class 3 has the effort in the middle. This formula applies to all three.
Results are computed from the standard equations of classical mechanics. Unit conversions use the SI definitions published by NIST. Air resistance is ignored unless the calculator names a drag model.
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Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026