Gear Ratio Calculator

Calculate gear ratios, output RPM, and torque for single or multi-stage gear systems. Visualize RPM and torque trade-offs.

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

Output Torque

Step-by-Step Solution

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.