Find ideal block-and-tackle effort Fin = mg / n and mechanical advantage MA = n.
| Effort (N) | – |
| MA | – |
Use this calculator for an ideal block and tackle: n is how many rope segments support the load, so MA = n and the effort is the load weight divided by n.
A gun tackle (n = 2) halves the effort; a luff (n = 3) divides by three. You pull a longer length of rope. Friction in real sheaves means you pull more than mg/n. g is taken as 9.80665 m/s².
Supporting strands: Integer count of ropes that share the load, at least 1.
Load mass (kg): Mass being lifted, in kilograms.
Effort (N): Ideal pull Fin = mg / n.
MA: Mechanical advantage, equal to n.
Related calculators