Gear Ratio Calculator

Calculate gear ratios, RPM, and torque transfer.

Enter Gear Parameters

Configure single or multi-stage gear system

Gear Configuration

Stage 1

Driver Teeth (T1)

Driven Teeth (T2)

Stage 2

Driver Teeth (T1)

Driven Teeth (T2)

Stage 3

Driver Teeth (T1)

Driven Teeth (T2)

Input RPM

RPM

Input Torque

N·m

Overall Gear Ratio

Output RPM

Configure your gear system above and tap Calculate to see the results.

Gear Ratio Formulas

GR = T2 / T1
RPM_out = RPM_in / GR
Torque_out = Torque_in × GR
Multi-stage: GR = GR1 × GR2 × GR3

T1: Driver gear teeth
T2: Driven gear teeth
GR > 1: Speed reduction (torque increase)
GR < 1: Speed increase (torque decrease)

Related Calculators

Pro Tips

Overdrive (GR < 1): Speed multiplier, torque reducer. Used for high-speed applications.

Underdrive (GR > 1): Torque multiplier, speed reducer. Used for heavy loads.

Multi-stage systems: Compound overall ratios for extreme speed/torque changes.