What this calculator does
Lever & mechanical advantage works out effort force needed to balance a load on a simple lever, from the arm lengths. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaFe·de = Fr·dr; mechanical advantage = de/dr = Fr/Fe
The inputs explained
| Field | What to enter |
|---|---|
| Load (resistance) force (N) | A number, measured in N. Starts at 500. |
| Load arm (fulcrum to load) (m) | A number, measured in m. Starts at 0.3. |
| Effort arm (fulcrum to effort) (m) | A number, measured in m. Starts at 1.2. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with load (resistance) force
Every other input is held at the calculator’s starting values while load (resistance) force varies. Select any row to load that scenario into the calculator.
How the answer changes with load (resistance) force