Perform fast calculations with our user-friendly online calculator! Conveniently crunch numbers and solve equations instantly. Ideal for quick math tasks, our tool simplifies your daily computations effortlessly. Try our intuitive calculator for accurate results on the go!
DC Motor Torque Calculator for fast and easy torque calculation using current, flux, torque constant, back EMF, power, and motor speed.
| Formula | Use When You Know | Notes |
|---|---|---|
| T_e = 60(V−IaRa)Ia ÷ 2πN | V, Ia, Ra, N | Back-EMF method — most direct from measurable steady-state values |
| T_e = Kt × Φ × Ia | Kt (or P,Z,A) and Φ, Ia | Fundamental electromagnetic torque equation |
| T_e = K × Ia | K, Ia | Simplified constant-flux form |
| T = 60P ÷ 2πN | Mechanical power P, speed N | ≈ 9550×P(kW)/N(rpm) rounded-constant approximation |
The DC Motor Torque Calculator helps you find the torque of a DC motor with ease. It supports four common ways to calculate motor torque. You can use motor torque constant, magnetic flux, armature current, back EMF, mechanical power, or motor speed.
This online DC motor torque calculator is useful for students, engineers, technicians, and anyone working with DC electric motors. It can also help you calculate motor torque from current.
The main DC motor torque formula is:
T = Kt × Φ × Ia
Here, T is motor torque in N·m. Kt is the torque constant. Φ is flux per pole in Weber (Wb). Ia is armature current in amperes (A).
The calculator also supports the DC motor torque equation:
T = Kt × Φ × Ia
If Kt is not known, the calculator can find it from:
Kt = PZ / (2πA)
Here, P is the number of poles. Z is the total armature conductors. A is the number of parallel paths.
For a constant-flux motor, the simplified torque formula is:
T = K × Ia
This shows that torque rises with armature current when the flux stays constant.
You can also calculate DC motor torque from voltage, current, resistance, and speed.
First, calculate back EMF:
Eb = V − Ia × Ra
Then calculate angular speed:
ω = 2πN / 60
The torque is:
T = Eb × Ia / ω
The calculator combines these steps into:
T = 60(V − Ia × Ra) × Ia / (2πN)
Here, V is supply voltage, Ia is armature current, Ra is armature resistance, and N is motor speed in RPM.
If you know mechanical power and motor speed, use:
T = 60P / (2πN)
When P is in watts, the result is in N·m.
A common shortcut is:
T = 9550 × P(kW) / N
This form is useful for a motor torque calculator when power is given in kilowatts.
Suppose a DC motor has:
Kt = 0.8
Φ = 0.05 Wb
Ia = 10 A
Use the main DC motor torque formula:
T = Kt × Φ × Ia
T = 0.8 × 0.05 × 10
T = 0.4 N·m
So, the motor's calculated electromagnetic torque is:
T = 0.4 N·m
For a back-EMF example, suppose V = 220 V, Ia = 20 A, Ra = 0.5 Ω, and N = 1500 RPM.
Eb = 220 − (20 × 0.5) = 210 V
ω = 2π × 1500 / 60 = 157.08 rad/s
T = (210 × 20) / 157.08
T ≈ 26.74 N·m
The DC Motor Torque Calculator makes motor torque calculation fast and simple. It supports the main DC motor torque formula, constant-flux torque, back-EMF torque, and mechanical power torque. Choose the method that matches your available data, enter the values, and get the torque in your preferred unit.
The basic formula is T = Kt × Φ × Ia. Torque depends on the torque constant, flux, and armature current.
For a constant-flux motor, use T = K × Ia. If Kt and flux are known, use T = Kt × Φ × Ia.
The standard electromagnetic torque equation is T = Kt × Φ × Ia. It can also be written as T = PZΦIa / (2πA).
Yes. If speed and armature resistance are also known, use T = 60(V − Ia × Ra) × Ia / (2πN).
Yes, if the required motor values are known. A 12V rating alone is not enough to determine torque. Current, resistance, speed, or the motor's torque constant may also be needed.
The basic torque relation can apply to BLDC motors, but BLDC motor modeling can use different constants and operating assumptions. This calculator is designed around the DC motor equations described above.