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Calcimator

Gear Ratio Calculator

Calculate gear ratio, output speed, output torque, and mechanical advantage for a simple gear pair.

Inputs

RPM
ft·lb

Results

Gear Ratio

3:1

Output Speed

600 RPM

Output Torque

147 ft·lb

Speed Reduction66.7%
Mechanical Advantage2.94
How to Use This Calculator
  1. Enter the number of teeth on the Driver Gear (pinion) — the input gear connected to the motor.
  2. Enter the number of teeth on the Driven Gear — a larger tooth count reduces output speed and multiplies torque.
  3. Enter the Input Speed in RPM — common motor speeds are 1200, 1800, and 3600 RPM.
  4. Enter the Input Torque in ft·lb, or calculate it as T = 5252 × HP / RPM.
  5. Read the Gear Ratio, Output Speed in RPM, and Output Torque in ft·lb — these are the key design values.
  6. Check the Mechanical Advantage and Speed Reduction % to confirm they meet your application requirements.
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