Motor Torque Calculator
Convert between motor power, speed and torque, and check starting torque.
About Motor Torque Calculator
Torque is power divided by angular velocity, so a low-speed motor produces far more torque for the same power. That is why gearboxes trade speed for torque rather than creating either. Starting torque must exceed the load’s breakaway torque or the motor will stall, which is the first check in any drive selection.
Formula
Motor Torque
T = P ÷ ω, with ω = 2π n ÷ 60
- T
- Torque in newton metres
- ω
- Angular velocity in radians per second
Worked example
With the default values below, Motor Torque Calculator returns Full-Load Torque of 98.446. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Motor powerminimum 0 kW
- 15 kW
- Shaft speedminimum 1 rpm
- 1,455 rpm
- Starting torque multipleaccepts 0.1–5 x
- 2 x
Results
- Full-Load Torque
- 98.446 N m
- Starting Torque
- 196.893 N m
- Full-Load Torque
- 72.610 lb ft
- Angular Velocity
- 152.367 rad/s
- Power at Double Speed and Same Torque
- 30.000 kW
Step by step
- 1Values used
- 2Motor Torque
- 3Full-Load Torque= 98.446 N m
- 4Starting Torque= 196.893 N m
- 5Full-Load Torque= 72.610 lb ft
- 6Angular Velocity= 152.367 rad/s
- 7Power at Double Speed and Same Torque= 30.000 kW
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Motor Torque calculated?
T = P ÷ ω, with ω = 2π n ÷ 60 Torque is power divided by angular velocity, so a low-speed motor produces far more torque for the same power. That is why gearboxes trade speed for torque rather than creating either.
Why does Motor Torque matter?
Starting torque must exceed the load’s breakaway torque or the motor will stall, which is the first check in any drive selection.
What values do I need to enter?
This calculator takes 3 inputs: Motor power, Shaft speed, Starting torque multiple. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.