Simple Pulley Calculator

Choose from four pulley configurations and see how they reduce the force needed to lift a load. Interactive SVG diagrams show the rope path, pulleys, and force arrows. All calculations run in your browser.

Fixed Pulley

Load (W)Effort (F)Tension segmentsPulley

Pulley Configuration

Parameters

Load (N)

Efficiency (η)

50% (high friction)100% (ideal)

Rope Length (m)

Presets

Results

Mechanical Advantage

1

Effort Force

100.00 N

Velocity Ratio

1

Ideal Effort

100.00 N

Work and Efficiency

Work Output (useful work)100.00 J

Work Input (total effort)100.00 J

Rope Distance (per 1 m lift)1.00 m

Efficiency100.0%

100.0%

0%Useful work / Total work100%

Step-by-Step Solution

1

\text{Fixed pulley: changes direction only}

2

MA = 1

3

F_{\text{ideal}} = \frac{W}{MA} = \frac{100}{1} = 100 \text{ N}

4

F_{\text{effort}} = F_{\text{ideal}} = 100 \text{ N}

5

VR = MA_{\text{ideal}} = 1

6

d_{\text{rope}} = d_{\text{load}} \times MA = 1 \times 1 = 1 \text{ m}

7

W_{\text{out}} = W \times d_{\text{load}} = 100 \times 1 = 100 \text{ J}

8

W_{\text{in}} = F_{\text{effort}} \times d_{\text{rope}} = 100 \times 1 = 100 \text{ J}

9

\eta = \frac{W_{\text{out}}}{W_{\text{in}}} = \frac{100}{100} = 100\%

Reference Guide

Types of Pulleys

A fixed pulley is attached to a support. It changes the direction of force but provides no mechanical advantage (MA = 1).

A movable pulley is attached to the load and moves with it. Two rope segments support the load, giving MA = 2.

A compound pulley combines a fixed and movable pulley. The fixed pulley redirects the rope to the movable pulley, giving MA = 2.

Mechanical Advantage

Mechanical advantage is the ratio of load to effort. It tells you how many times the pulley system multiplies your input force.

Ideal MA

MA = \frac{W}{F_{\text{effort}}}

For n supporting rope segments

MA = n

The trade-off is distance. To lift a load 1 m with MA = 4, you must pull the rope 4 m.

Work and Energy in Pulleys

In an ideal (frictionless) pulley, work input equals work output. You trade force for distance.

Work output

W_{\text{out}} = F_{\text{load}} \times d_{\text{load}}

Work input

W_{\text{in}} = F_{\text{effort}} \times d_{\text{rope}}

Efficiency

\eta = \frac{W_{\text{out}}}{W_{\text{in}}} \times 100\%

Real-World Pulley Systems

Real pulleys have friction at the axle and rope stiffness, so efficiency is always less than 100%. Typical efficiencies range from 70% to 95% per pulley.

Block and tackle systems use multiple pulleys threaded with a single rope to achieve high mechanical advantage. A 6-pulley block and tackle can let one person lift a car engine.

Cranes, elevators, flagpoles, and sailing ships all rely on pulley systems. Construction cranes often combine dozens of pulleys to lift loads of several tons.

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Simple Pulley Calculator

Fixed Pulley

Pulley Configuration

Parameters

Presets

Results

Work and Efficiency

Step-by-Step Solution

Reference Guide

Types of Pulleys

Mechanical Advantage

Work and Energy in Pulleys

Real-World Pulley Systems

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