Fulcrum Calculator

Use this fulcrum calculator to determine a lever's fulcrum location from the load you want to lift.

Force on the fulcrum1 kNeffort and load both push down, so the fulcrum carries their sum

Effort needed200 N800 N ÷ a mechanical advantage of 4

Mechanical advantage4×the lever multiplies your force

Lever classFirst class — fulcrum between effort and load, like a crowbar or see-saw

Distance the effort must move4× the load's movementa lever trades distance for force — the work done is identical either way

Load moved per metre of effort travel0.25 m

Work to raise the load 100 mm80 Jthe same whatever the lever, which is the point

Total lever length1.5 m

Effort arm needed to halve the effort2.4 m

The formula

MA = effort arm ÷ load arm; effort × effort arm = load × load arm

Force for distance, never something for nothing

A lever multiplies force by the ratio of its arms, and divides movement by exactly the same ratio. Lift a 800 N load with 200 N of effort and you must move your end four times as far. The work — force times distance — is identical, which is what "no machine creates energy" means in practice.

The three classes differ in what sits between what. First class puts the fulcrum in the middle and can give an advantage above or below one depending on where you push. Second class puts the load in the middle and always gives an advantage above one — a wheelbarrow. Third class puts the effort in the middle and always gives an advantage below one, which sounds useless until you notice that it buys speed and range instead: that is why your forearm is built that way, and why a small muscle contraction throws a ball fast.

The fulcrum load is worth checking in any real design. On a first-class lever it carries the sum of effort and load, which can be considerably more than the load alone.