Free Gear Speed Calculator | Input/Output RPM & Pitch Line Velocity

Calculate rotational speed and surface velocity across mating gears and gear trains. Input your motor RPM, set tooth counts, and immediately calculate output shaft RPM, angular velocity, and pitch line linear velocity (v = ω × r). Watch your gear train spin at exact relative speeds in real time.

Key Features

• Computes output RPM from input motor speed and gear ratio (RPM_out = RPM_in / Ratio)
• Calculates linear pitch line velocity in meters/sec and feet/min
• Interactive visual simulation: slider controls input speed from 1 to 1000 RPM
• Verifies rotational directions (same direction for internal gears, opposite for spur gears)
• Export production DXF and SVG geometry for CAD and digital fabrication
• 100% free online calculator with instant browser execution

Frequently Asked Questions

What is the formula for calculating gear RPM?

RPM_driven = RPM_driver × (Teeth_driver / Teeth_driven). For example, a 20-tooth gear spinning at 1000 RPM driving a 40-tooth gear turns the driven shaft at 500 RPM.

What is pitch line velocity and why does it matter?

Pitch line velocity (v = π × D × RPM) is the linear speed at which gear teeth contact. High pitch line velocities require precision tooth grinding, balancing, and active lubrication.

How does an idler gear affect output speed?

An idler gear does not change output speed or gear ratio. It only changes the direction of rotation and spans physical center distance between shafts.