How this calculator works
Ideal mechanical advantage follows the ratio of input travel to output travel. Lever and wheel models use radii or perpendicular arms; a screw uses one effort-circle circumference per lead; a ramp uses slope length divided by rise. For a tackle, count rope segments supporting the moving load rather than the number of pulley wheels. Wedge length and thickness describe the ideal displacement ratio. These formulas assume no friction or deformation.
Formula
Lever: MA=effort arm/load arm. Pulley: MA=supporting strands. Screw: MA=pi D/lead. Wedge: MA=length/thickness. Ramp: MA=slope length/rise=1/sin(inclination). Wheel: MA=wheel radius/axle radius. Fout=MA Fin.
Worked example
A 2 m effort arm and 0.5 m load arm give advantage 4, converting 10 N ideally to 40 N. A screw with a 0.1 m effort circle and 0.01 m lead has ideal advantage 31.4159.
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Frequently asked questions
Why count strands instead of pulley wheels?
Only strands pulling directly on the moving block support the load. A fixed redirecting pulley may add no force advantage.
Is screw lead the same as thread pitch?
Only for a single-start thread. Lead equals pitch multiplied by the number of starts.
Can actual advantage equal the ideal figure?
Losses usually make actual force advantage smaller. This tool does not estimate friction or efficiency.