Pulley Ratio Calculator
Calculate pulley ratio, output speed (RPM), and torque in belt drive systems
Calculator
Enter pulley diameters and input RPM to calculate pulley ratio, output speed, and torque change.
About the Pulley Ratio Calculator
The Pulley Ratio Calculator helps you quickly determine the speed and torque changes that occur in belt-driven pulley systems. By entering the diameters of the driver and driven pulleys, along with input RPM, the calculator provides pulley ratio, output speed, and theoretical torque multiplication. This tool is ideal for mechanical engineers, technicians, and students working with power transmission systems.
What You Can Calculate
- Pulley Ratio: Ratio of driver to driven pulley diameters.
- Output Speed (RPM): Speed of the driven pulley.
- Torque Multiplication: Approximate torque increase or decrease caused by the pulley size change.
- Speed Reduction or Increase: Determine if the mechanism speeds up or slows down the output shaft.
Formulas Used in the Calculator
- Pulley Ratio: Ratio = D₂ / D₁
- Output RPM: RPM₂ = RPM₁ × (D₁ / D₂)
- Torque Change (ideal): T₂ = T₁ × (D₂ / D₁)
How to Use the Calculator
- Enter the driver pulley diameter.
- Enter the driven pulley diameter.
- Enter the input RPM from the motor or source.
- The calculator instantly displays pulley ratio, output RPM, and torque change.
Applications of Pulley Ratio Calculation
Pulley ratio calculations are critical for machinery design, automotive systems, HVAC fans, industrial conveyors, and power transmission engineering. Understanding pulley ratios helps optimize speed, torque, and mechanical efficiency in rotating systems.