Pulley Mechanical Advantage Calculator
Estimate effort and rope travel from the number of load-supporting rope segments. Compare ideal geometry with an entered overall lifting efficiency.
YOUR CALCULATION
Result
—
Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Ideal geometry multiplies rope travel by the number of supporting segments. Work balance with an overall efficiencyη gives input work=output work/η and effort=load/(segments×η).
Rope travel=nh; effort=W/(nη); output work=Wh
Worked example
A200N load lifted1m with4 supporting segments and80% efficiency needs62.5N effort and4m rope travel. Output work is200J and input work250J.
Assumptions and input details
Count rope segments actually supporting the moving load, not the number of pulley wheels. Assume parallel supporting segments, steady lifting and a fixed geometry. Enter1–20 segments and0<efficiency≤100%. Moving pulley/block weight must be included in the entered load if relevant. Elasticity, starting acceleration and changing rope angles are omitted. Entered base-unit magnitudes are limited to1e12 unless a tighter limit is stated. Results use floating-point arithmetic. These are ideal-model estimates, not equipment load ratings.
References: OpenStax simple machines
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Choose from 23 length definitions, including explicitly labelled regional measures. Area conversions square the length factor; geometric volumes cube it.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
Find the effort force needed to balance a load about a fulcrum. Compare perpendicular moment arms, torque and ideal mechanical advantage.
Resolve two forces into a resultant, or check whether a block can stay at rest on an incline. Inspect components, friction limits and acceleration after slipping begins.
Find translational kinetic energy, mass or speed from the other two values. Choose explicit units, compare energy equivalents and see how energy changes with speed.
Reserved advertising space.