Planetary Gear Calculator

Calculate gear ratios, speeds, and torques for epicyclic (planetary) gear trains with sun, planet, and ring gears.

Number of teeth on the sun gear.
Number of teeth on the ring. Must equal Zs + 2*Zp.
Input speed at the sun gear.
rpm
Torque applied to the sun gear.
N·m
Number of planet gears (typically 3 or 4).

Results

Planet Gear Teeth-
Gear Ratio (ring fixed)-
Output Speed (carrier)-rpm
Output Torque-N·m
Assembly Condition-
References: Shigley's — Gear Trains; Dudley's Gear Handbook