Gearbox & Pulley Calculator

Ratio, output speed and torque for gearboxes and pulleys.

READY

gearbox__pulley_calculator.tool

READY

Ratio source

Direct (i)Tooth countPulley diameter

Teeth drive z1

Teeth driven z2

Drive speed [U/min]

Drive torque [Nm](optional)

Efficiency [%](optional)

Ratioi = 5

Output speed290 U/min

Output torque47.5 Nm

Drive power1.518 kW

// HOW IT WORKS

A gearbox or pulley pair changes speed and torque. The tool computes the ratio, the output speed and the output torque.

Formula

i = n_in / n_out = z_out / z_in
M_out = M_in · i · η

Example

z_in = 20, z_out = 60 → i = 3; n_in = 1500 1/min → n_out = 500 1/min; M_in = 10 Nm, η = 0.95 → M_out ≈ 28.5 Nm.

Notes

A reduction (i > 1) lowers speed and raises torque by the same factor (minus losses).
η accounts for friction/efficiency; for an ideal stage set η = 1.