Free Gear Train Calculator & Multi-Stage Speed Reduction Simulator

Design and analyze complex multi-stage gear trains. GearDXF automates gear train kinematics: connect multiple gears on shared axles (compound gears) or in mesh sequences (idler gears). Automatically calculate overall velocity ratios, output RPM, mechanical advantage, and rotation directions in real time.

Key Features

• Supports simple gear trains, idler gears, and compound multi-axle trains
• Computes total reduction ratio as the product of individual gear stages
• Interactive visual canvas with automatic center distance snapping
• Visualizes forward and reverse directional kinematics dynamically
• Export the entire connected gear train to DXF and SVG for manufacturing
• Completely free browser tool with no calculation limits

Frequently Asked Questions

What is the purpose of an idler gear in a gear train?

An idler gear is placed between a driver and driven gear. It changes the direction of rotation and bridges physical distance without affecting the overall gear ratio.

How does a compound gear train achieve large speed reductions in a small space?

By keying a large gear and a small gear onto the same rotating axle, each stage multiplies the reduction ratio (Ratio_total = R1 × R2 × R3), achieving massive speed reduction in a compact gearbox.

How do I calculate output torque across a gear train?

Output torque is approximately equal to Input Torque × Gear Ratio × Mechanical Efficiency (typically 95-98% per gear mesh).