Lever and mechanical advantage calculator
Enter the load, its distance from the fulcrum and the distance where you push, and get the force needed to balance it. Works for all three lever classes.
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How to use it
- Enter load, load arm (distance to fulcrum) and effort arm (distance to fulcrum).
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Moment balance about the fulcrum: effort × effort arm = load × load arm, so effort = load × load arm ÷ effort arm. Mechanical advantage = effort arm ÷ load arm.
Example
Inputs: Load = 1,000 N, Load arm (distance to fulcrum) = 0.5 m, Effort arm (distance to fulcrum) = 2 m. Result: Effort needed: 250 N; Mechanical advantage: 4; Effort in kilogram-force: 25.493 kgf.
Limits and caveats
- Ignores the weight of the lever and friction at the fulcrum.
- Assumes both forces act at right angles to the bar. For an angled force, use the perpendicular distance.
Questions about this tool
Does it work for every lever class?
Yes. As long as both arms are measured from the fulcrum, the moment equation is the same for all three classes.
How do I turn kilograms into newtons?
Multiply the mass by 9.80665, so a 100 kg load is about 980.7 N.
Why is the mechanical advantage sometimes below 1?
When the effort arm is shorter than the load arm, as in tweezers, you push harder but gain movement and speed.