Motor Torque Calculator

Calculate motor torque instantly using power and speed. Enter input power in kW or HP and speed in RPM to get torque in N·m or lb·ft for any motor type.

motor torque from power and rpm calculator:

A Motor Torque Calculator helps determine the rotational torque a motor generates based on its power output and speed. Torque is the twisting force that produces rotation. The standard formula is T = (9550 × P) / N, where T is torque in newton-metres (N·m), P is motor power in kilowatts (kW), and N is rotational speed in revolutions per minute (RPM). Alternatively, in imperial units, T(lb·ft) = (5252 × HP) / RPM. This simple tool allows engineers to verify motor sizing, analyze shaft loads, and ensure mechanical compatibility with the driven equipment.

Work & Installation — Input to Output Summary

Work Principle: Motor torque represents the rotational effort produced by a motor’s shaft. It links electrical power and mechanical motion: higher torque means greater rotational force.

Installation Setup: Add inputs for Motor Power (choose unit: kW or HP) and Speed (RPM). Include dropdown for unit output selection (N·m or lb·ft).

Input: User enters motor power and speed.

Calculation:
For metric: \( T(N.m) = \frac{9550 \times P_{kw}}{N_{RPM}} \)
For imperial: \( T(Ib.ft) = \frac{5252 \times P_{HP}}{N_{RPM}} \)

Output: Display torque in selected units, optionally include reverse calculation (Power from Torque & RPM).

Interpretation: Higher torque indicates more load-handling capacity. Engineers use torque data to design couplings, belts, and shafts that can withstand applied mechanical forces.

Testing and Final Adjustments

Test the calculator with known motor ratings.
Example 1: Power = 5 kW, Speed = 1500 RPM → T = (9550 × 5) / 1500 = 31.83 N·m.
Example 2: Power = 10 HP, Speed = 1800 RPM → T = (5252 × 10) / 1800 = 29.18 lb·ft.
Verify that both unit systems yield correct results. Add form validation to prevent division by zero or blank entries. Ensure output updates dynamically and rounds values neatly. Include a reset button and tooltips explaining each formula. Test across browsers (Chrome, Edge, Firefox) and mobile devices for responsive layout. Finally, cross-check calculator accuracy against standard motor datasheets. Ensure the UI clearly displays “Torque = … N·m” and optional “Convert to lb·ft” link for user convenience.

Frequently Asked Questions - Motor Torque Calculator:

What is motor torque?

Motor torque is the rotational force generated by a motor’s shaft that causes it to spin.

How do I calculate torque from power and speed?

Use T=(9550×P)/N for kW and RPM, or T=(5252×HP)/RPM for HP and RPM.

What units are used for torque?

Torque is measured in newton-metres (N·m) or pound-feet (lb·ft).

Can I use this for both AC and DC motors?

Yes, the formula applies to all motor types since it’s based on power and speed.

What does higher torque mean?

Higher torque means the motor can apply more rotational force to the load.

How is torque related to power?

Power equals torque times angular speed; they are directly proportional for a given speed.

What if my power is in watts?

Convert watts to kilowatts by dividing by 1000 before using the formula.

Can the calculator convert torque to horsepower?

Yes, by rearranging the formula HP=(Torque×RPM)/5252.

Does torque depend on efficiency?

The formula gives mechanical output torque; if input torque is needed, include efficiency.

Why calculate motor torque?

To ensure correct motor sizing, prevent overload, and design mechanical systems effectively.

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Motor Torque Calculator | Torque from Power and Speed Formula