Free Planetary Gear Generator & Epicyclic Gearbox Calculator

Design planetary (epicyclic) gear systems directly in your browser. Calculate the fundamental gear ratio relationship between sun, planet, and ring gears (Z_ring = Z_sun + 2 × Z_planet). Simulate carrier and ring rotation dynamics and export production-ready DXF and SVG files for CNC and 3D printing.

Key Features

• Automatic tooth count verification for planetary meshing
• Calculates carrier fixed, sun fixed, and ring fixed gear ratios
• Simulates multi-planet meshing and same-direction ring rotation
• Custom backlash compensation for 3D printed planetary gearboxes
• Instant DXF, SVG, and 1:1 scale printable PDF export
• 100% free with no plugins, ads, or account requirements

Frequently Asked Questions

What is the fundamental tooth relationship for planetary gears?

For symmetrical meshing, the ring gear tooth count must equal the sun gear tooth count plus twice the planet gear tooth count: Z_ring = Z_sun + 2 × Z_planet.

How many planets can I assemble in a planetary gear set?

Typically 3 or 4 planets are used. To ensure equal spacing around the sun gear, (Z_sun + Z_ring) must be evenly divisible by the number of planets.

How do I export planetary gears for 3D printing?

Select DXF or SVG in GearDXF. Use the backlash setting (recommended 0.2mm to 0.4mm for FDM printers) to prevent the sun, planets, and ring gear from fusing during printing.