When working with motors—whether in robotics, electric vehicles, or industrial applications—stall torque is one of the most critical performance characteristics to understand. Knowing the stall torque allows engineers, hobbyists, and students to predict motor behavior under maximum load. That’s where our Stall Torque Calculator comes into play.

This easy-to-use online tool helps you compute stall torque quickly by using the stall current and the torque constant. No complex math or manual calculations are needed—just enter the required values, click a button, and get an instant result.

In this article, you’ll learn what stall torque is, how the calculator works, how to use it properly, its formula explained in simple text, real-world examples, and 20 frequently asked questions to clear any doubts.

What is Stall Torque?

Stall torque is the maximum torque a motor can generate when the output shaft is not rotating. In other words, it’s the force the motor can apply at zero speed.

When a motor is “stalled”—meaning it’s trying to move but cannot because of an external load or blockage—it produces the highest torque it can. However, maintaining stall conditions can damage the motor over time, so understanding and managing stall torque is crucial.

Stall Torque Formula Explained

The stall torque can be calculated using a very simple formula:

Stall Torque (N-m) = Stall Current (A) × Torque Constant (N-m/A)

Where:

Stall Current is the maximum current drawn by the motor at zero speed.
Torque Constant is a value that defines how much torque a motor generates per unit of current.

Example in plain text:
If a motor has a stall current of 50 Amperes and a torque constant of 0.05 Newton-meters per Ampere, then:

Stall Torque = 50 × 0.05 = 2.5 Newton-meters

How to Use the Stall Torque Calculator

Using our online Stall Torque Calculator is very straightforward. Here’s a step-by-step guide:

Enter Stall Current:
Input the stall current value of your motor in Amperes (A) into the first box.
Enter Torque Constant:
Provide the torque constant of your motor in Newton-meters per Ampere (N-m/A) in the second box.
Click on “Calculate”:
Press the “Calculate” button, and the calculator will instantly show the stall torque value in Newton-meters.
Read the Result:
The result box will display the stall torque based on the entered values.

It’s that easy! No need for manual calculations or complex formulas.

Real-Life Example

Imagine you are working on designing an electric bike motor. You have a motor with these specs:

Stall Current = 120 A
Torque Constant = 0.03 N-m/A

Using the formula:

Stall Torque = 120 × 0.03
Stall Torque = 3.6 N-m

Thus, the motor can exert a maximum of 3.6 Newton-meters of torque when it is stalled.

Using the Stall Torque Calculator, you would simply input:

Stall Current: 120
Torque Constant: 0.03
Click “Calculate” → Result: 3.6 N-m

Why Stall Torque is Important

Understanding stall torque is essential for several reasons:

Motor Selection: Ensures you choose the right motor for your load requirements.
Prevent Overheating: Prevents damage caused by running motors under stall conditions.
Optimize Performance: Helps balance speed, torque, and efficiency.
Improve Safety: Prevents mechanical failures in critical systems.

Without knowing the stall torque, you risk underestimating or overestimating your system’s capabilities.

Advantages of Using Our Stall Torque Calculator

Instant results with no complex math.
User-friendly interface—simply input values and get answers.
Accurate computations every time.
Saves time for engineers, hobbyists, and students.
Helps in quick decision-making during design and testing.

Additional Information

Here are some helpful insights you should know when working with motors and stall torque:

High Stall Torque vs. Low Stall Torque: Motors with higher stall torque can move heavier loads but might consume more current.
Continuous Torque vs. Stall Torque: Continuous torque is the maximum torque the motor can apply indefinitely without overheating, while stall torque is a short-term maximum torque.
Motor Damage at Stall: Continuously operating a motor at stall current can overheat and damage it.
Torque Constant Units: Always ensure the units match (N-m per A) for accurate calculations.

20 FAQs About Stall Torque Calculator

Q1: What is stall torque?
Stall torque is the maximum torque a motor can generate at zero speed.

Q2: How do I find the stall current of my motor?
You can usually find it in the motor’s datasheet provided by the manufacturer.

Q3: What is a torque constant?
The torque constant indicates how much torque a motor produces per ampere of current.

Q4: Can stall torque damage my motor?
Yes, operating at stall torque for extended periods can overheat and damage the motor.

Q5: What units are used in this calculator?
Stall current in Amperes (A) and torque constant in Newton-meters per Ampere (N-m/A).

Q6: Can I use this calculator for AC motors?
This calculator is primarily designed for DC motors but can be adapted with proper torque constants.

Q7: What if I input wrong values?
Incorrect inputs will give wrong results. Always double-check your motor specifications.

Q8: Is the calculator free to use?
Yes, it’s completely free.

Q9: How accurate is this calculator?
It is highly accurate as long as correct input values are provided.

Q10: What happens if stall current is zero?
If stall current is zero, the stall torque will also be zero.

Q11: How can I calculate torque without a torque constant?
You need the torque constant; otherwise, calculation isn’t possible using this method.

Q12: Does a higher torque constant mean a stronger motor?
Not necessarily. You need to consider both torque constant and maximum current.

Q13: Can I use different units like pound-inches?
This calculator only works in SI units. You need to convert to N-m first.

Q14: What is the typical stall torque for small motors?
It can range from 0.01 N-m to 5 N-m depending on the motor type.

Q15: Why is my stall torque reading very low?
It could be due to a low torque constant or low stall current.

Q16: How do electric vehicles use stall torque?
High stall torque helps electric vehicles achieve quick acceleration from a stop.

Q17: Is stall torque the same as starting torque?
For many motors, yes. Stall torque often equals starting torque.

Q18: What safety measures should be taken when measuring stall torque?
Always avoid holding a motor at stall for long; use proper sensors and cooling if needed.

Q19: What else affects motor torque?
Factors like temperature, voltage, and motor efficiency affect torque.

Q20: Can the calculator predict motor lifespan?
No, it only calculates stall torque, not motor wear or lifespan.

Final Thoughts

Understanding stall torque is crucial for anyone working with motors, and using a Stall Torque Calculator makes the process incredibly simple and accurate. Whether you’re building a robot, designing an electric car, or creating a machine, knowing the stall torque helps you make smarter decisions and protect your equipment.

So the next time you need to calculate stall torque, save yourself the hassle—use our easy Stall Torque Calculator and get reliable results instantly!