Motor Torque Calculator

Calculate motor torque and gearbox output torque based on power, speed, and reduction ratio.

Formula: T = 9550 * P / n * i * η
kW
RPM
:1
Use 1.0 for ideal, typically ~0.9 for gearboxes

Results

Motor Rated Torque
- N·m
T = 9550 * P / n
Gearbox Output Torque
- N·m
Includes reduction ratio and efficiency
Output Speed
- RPM

Calculation Notes

Basic Formula

Torque Formula: T = 9550P / n

  • T: Torque in N·m
  • P: Output Power in kW
  • n: Motor Speed in r/min (RPM)

Gearbox Torque Calculation

When using a reducer, the output torque increases. The formula is:

Output Torque = 9550 × Power × Ratio × Efficiency / Speed

Or: Output Torque = Motor Torque × Ratio × Efficiency

Example

0.75kW motor, ratio 1:30, speed 1380 RPM:

Torque = 0.75 × 9550 × 30 / 1380 ≈ 155.7 N·m

Units

1 kg·m ≈ 9.8 N·m (approx. 10 N·m)

Understanding kg·m: 22.6 kg·m means it can lift 22.6kg at the edge of a 1m radius circle.