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Earth Bondhon
Last updated: Jun 3, 2026

Motor Torque Calculator

Calculate torque of DC or AC motors using power and speed, or current and voltage. Essential for performance evaluation, motor sizing, and design.

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Motor Torque Calculator

Calculate torque of DC or AC motors using power and speed, or current and voltage. Essential for performance evaluation, motor sizing, and design.

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Motor Torque Calculator:

Motor torque is the rotational force produced by a motor to drive a load. The Motor Torque Calculator computes torque from power, speed, or current, helping engineers and students optimize motor performance and design.

Motor Torque Tools formula

The Motor Torque Calculator computes the torque produced by a motor based on input parameters such as electrical power, mechanical power, speed, current, and voltage. Torque is a critical factor for motor performance, load handling, and design optimization.
Formulas used:

From Power and Speed:

\[ \textrm{T (Nm)} = \frac{(P \times 60)}{2 \times \pi \times N} \]

Where: P = mechanical power (W), N = speed in rpm

\[ \textrm{T (Nm)} = K \times I_{a} \]

Where: I_a = armature current (A), k = torque constant (Nm/A)

This calculator is suitable for engineers, technicians, and students to quickly evaluate torque in DC and AC motors, aiding in motor selection, load analysis, and performance evaluation. It provides instant torque results for accurate motor sizing and energy analysis.

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Work & Installation — Input to Output Summary

Work:

  • Calculates torque for DC and AC motors.
  • Supports calculations from power-speed or current-torque constant.
  • Useful for performance evaluation, motor sizing, and load analysis.

Installation:

  • Add HTML input fields for mechanical power, speed, current, and torque constant.
  • Include JavaScript formulas:
    \( \textrm{T (Nm)} = \frac{(P \times 60)}{2 \times \pi \times N} \)
    \( \textrm{T (Nm)} = K \times I_{a} \)
  • Display output in newton-meters (Nm).

Input:

  • Mechanical Power (P, W)
  • Speed (N, rpm)

Output:

  • Armature Current (I_a, A)
  • Torque Constant (k, Nm/A)

Testing and Final Adjustments

Test with example: P = 1000 W, N = 1500 rpm → T = (1000 × 60) / (2 × π × 1500) ≈ 6.37 Nm. For current method: I_a = 10 A, k = 0.5 Nm/A → T = 5 Nm. Verify calculations for both DC and AC motor scenarios. Ensure decimal inputs are handled correctly and prevent negative or zero values. Include real-time calculation updates for better usability. Optionally, provide graphical torque-speed relationship. Validate responsiveness on desktop and mobile. Ensure unit consistency and rounding. After verification, finalize layout, tooltips, input validation, and display formatting to provide accurate torque assessment for educational, professional, and industrial applications. This tool helps engineers optimize motor selection, performance, and load management.

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Frequently Asked Questions - Motor Torque Calculator:

Motor torque is the rotational force produced by a motor shaft and is typically measured in Newton-meters (Nm) or pound-feet (lb-ft).
Torque is calculated by dividing motor power by angular speed. The formula is Torque = Power / Angular Speed.
The common formula is Torque (Nm) = (9550 × Power in kW) / Speed in RPM.
Yes, torque can be estimated using current and voltage by first calculating electrical power and then applying motor efficiency and speed.
The basic torque formula is the same, but AC motors require consideration of power factor and efficiency.
Torque determines a motor’s ability to start loads and handle mechanical resistance, making it critical for proper motor sizing.
Torque is commonly measured in Newton-meters (Nm), kilogram-meter (kg·m), or pound-feet (lb-ft).
For a given power, higher speed results in lower torque, while lower speed produces higher torque.
Motor efficiency affects the usable mechanical power, which directly impacts the calculated torque value.
Torque calculations are used in motor design, performance evaluation, mechanical load analysis, and industrial equipment selection.
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