Lever Mechanical Advantage Calculator
Compute a lever’s mechanical advantage from its effort and load arm lengths, and the effort force needed to lift a load.
How it works
Mechanical advantage = effort arm ÷ load arm · Effort force = load ÷ mechanical advantage
A lever’s ideal mechanical advantage is the ratio of the effort arm (fulcrum to where you push) to the load arm (fulcrum to the load). An MA above 1 multiplies your force, so a long effort arm lets a small push move a big load — but that push has to travel proportionally farther, because the lever conserves work (force × distance). Friction makes the real advantage slightly lower than this ideal figure.
Worked example
A crowbar with a 120 cm effort arm and a 30 cm load arm has MA = 120 ÷ 30 = 4. To lift a 600 N load you need only 600 ÷ 4 = 150 N of effort — but your end of the bar must move four times as far as the load rises.
Sources: Lever — Wikipedia
Frequently asked questions
What is the trade-off for more mechanical advantage?
Distance. A lever conserves work, so if it multiplies your force by 4 it also makes your hand travel 4 times the distance the load moves. You never get force and distance for free at the same time.
Where should the fulcrum go to lift a heavy load?
Close to the load. The shorter the load arm and the longer the effort arm, the greater the mechanical advantage — which is why you place the fulcrum near what you want to lift.
What does an MA below 1 mean?
It means the effort arm is shorter than the load arm, so you trade force for speed and range of motion. Tools like tweezers and a fishing rod work this way, moving the load a long way with a small hand motion.
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This calculator is for educational purposes. Double-check important results before acting on them.