Gear Ratio Calculator

Mechanical Advantage & Speed

Calculate gear ratios for simple and compound gear systems. Find mechanical advantage, output speed, and vehicle velocity.

Calculator

Formula:
Gear Ratio = Driven Teeth / Driving Teeth

About Gear Ratios

Gear ratio is the relationship between the number of teeth on two gears that are meshed.

Ratio > 1:

Speed reduction, torque multiplication

Ratio < 1:

Speed increase, torque reduction

Features

  • Simple gear ratio
  • Compound gear systems
  • Speed calculation
  • Mechanical advantage
  • Output RPM
  • Vehicle speed
  • Real-world examples
  • Copy results

Common Ratios

Bicycle:

2:1 to 4:1 (speed increase)

Car 1st Gear:

3:1 to 4:1 (reduction)

Overdrive:

0.7:1 (speed increase)

Differential:

3:1 to 4.5:1 (reduction)

Key Terms

Driving Gear: Input gear (power source)

Driven Gear: Output gear (load)

Compound Gears: Multiple gear pairs in series

Mechanical Advantage: Force multiplication

Applications

  • Automotive transmissions
  • Bicycle gear systems
  • Industrial machinery
  • Robotics
  • Clock mechanisms
  • Power tools
  • Conveyor systems
  • Wind turbines

Design Considerations

Important Factors:

Torque vs Speed: Higher ratio = more torque, less speed

Efficiency: Each gear pair loses ~2-5% efficiency

Backlash: Gap between meshing teeth

Load Capacity: Larger gears handle more power