Example 1: 7.5 kW motor at 1440 RPM
A motor delivers 7.5 kW at 1440 RPM.
T = (7.5 x 1000 x 60) / (2 x pi x 1440)
The shaft torque is approximately 49.74 N m.
Motor Torque Calculator
Calculate torque in N m from mechanical power and shaft speed.
Introduction
Motor torque is one of the most important quantities in machine and drive selection because it represents the turning force available at the shaft. Engineers use torque values when checking whether a motor can start a load, accelerate equipment, and maintain operation under real mechanical demand. Pumps, conveyors, compressors, fans, gearboxes, and process machines all depend on the correct torque-speed relationship.
This motor torque calculator estimates shaft torque from mechanical power and rotational speed. It provides a quick design value in newton-meters and is useful in electrical, mechanical, and industrial system design.
It is especially handy when checking whether a motor can meet the load demand of conveyors, fans, pumps, or driven equipment before moving into more detailed machine selection.
Formula
Basic relationship: T = P / omega
Practical calculator form: T = (P x 1000 x 60) / (2 x pi x n)
Practical calculator form: T = (P x 1000 x 60) / (2 x pi x n)
Variable Definitions
T = torque in newton-meters
P = mechanical power in kilowatts
n = rotational speed in revolutions per minute
omega = angular speed in radians per second
Units
Power is entered in kilowatts and speed is entered in RPM. The output is displayed in N m, which is the common SI unit used for motor shaft torque.
Worked Examples
Example 2: 15 kW motor at 960 RPM
A motor delivers 15 kW at 960 RPM.
T = (15 x 1000 x 60) / (2 x pi x 960)
The shaft torque is approximately 149.21 N m.
How To Interpret Motor Torque
The result shows how much turning force is available at the shaft for the stated output power and speed. This is useful when checking whether a motor can drive a pump, fan, conveyor, mixer, or gearbox without stalling or running outside the expected operating point. In many applications, torque matters more directly than power because it reflects the actual mechanical push available to move the load.
The value is also a reminder that speed and torque trade against each other. For the same general power level, a lower-speed motor produces more torque, which is why geared systems and low-speed drives can deliver very strong shaft force without needing the same rpm as a direct-drive machine.
Practical Notes
Always use mechanical output power when calculating shaft torque. Electrical input power should not be used directly unless motor efficiency is also taken into account. Starting torque, breakdown torque, and load variation can also matter in real applications, so this calculator should be used as a fast operating-point estimate rather than the only motor selection criterion.
In real selection work, compare the calculated running torque with the load torque curve, startup requirement, service factor, and duty cycle. A motor that is adequate at running speed may still struggle if the driven machine needs a high breakaway torque or frequent acceleration from standstill.