Gearbox Output Speed & Torque Calculator

Find the output speed and torque of a geared electric motor from the reduction ratio.

Motor speed (rpm)

Motor power (kW)

Reduction ratio i

Gearbox efficiency η

Output speed: — rpm

Input torque: — Nm

Output torque: — Nm

n_çıkış = n / i · T_çıkış = (9550·P/n) · i · η

How it works

A gearbox reduces speed by the ratio i and multiplies torque by i × efficiency. Pick the motor by the required output speed/torque and duty. See our power & speed range and electric motors. Related: torque calculator · pulley/belt.

How is gearbox output speed calculated?

Output speed = motor speed ÷ reduction ratio (n/i). A 1450 rpm motor with i=20 gives ~72.5 rpm.

How is output torque calculated?

Output torque = input torque × ratio × efficiency, where input torque = 9550 · P(kW) / n(rpm).

Why multiply torque by efficiency?

Gear meshing has losses; multiplying by η (≈0.9–0.97) gives the usable output torque.