Gear Ratio Calculator

A simple gear ratio calculator to find the speed and mechanical advantage of a gear system of spur gears. Gear ratio is determined solely by the number of teeth on each gear. Check the box if the gear is on the same shaft as the gear above it, leave it unchecked if the gear meshes with the gear above it.

Simple Gear Train

When there is only one gear fitted on each shaft, then this type of gearing system is called a simple gear-train. It is the ratio of the speed of the input gear to the speed of the output gear. The ratio speed of any pair of gears is the inverse to the number of teeth. The gear ratio is only determined by the input gear and the output gear. Intermediate gears are called idler gears and can only change the direction of rotation of the output, but not the gear ratio.

Compound Gear Train

An example of a compound gear-train is shown below: The Input Gear meshes with Gear 2. Gear 3 is on the same shaft as Gear 2, and meshes with Gear 4. Gear 5 is on the same shaft as Gear 4, and meshes with Gear 6. The "same shaft" boxes would be checked on Gears 3 and 5 only.

Library of available VEX IQ gears

VEX Motor Specifications

  • Connectors: (1) Smart Port
  • Free Speed: 120 rpm
  • Stall Torque: 0.414 N-m
  • Output Power: 1.4W
  • Command Rate: 3,000 Hz
  • Sample Rate: 3,000 Hz
  • Encoder Resolution: 0.375 degrees
  • Typical Operating Voltage: 7.2V
  • No Load Current: 100 mA
  • 1.4W peak output power: 7.2V