In the world of electric motors, particularly brushless motors, calculating the input power is critical for understanding the overall performance and efficiency of a motorized system. Whether you are designing drones, electric bikes, RC vehicles, or industrial machinery, knowing the input power helps ensure that your motor operates safely and efficiently.

Our Brushless Motor Power Calculator tool makes it incredibly easy for you to determine the motor’s input power simply by entering two key values: output power and efficiency. No more tedious hand calculations or risking mistakes — our tool delivers instant, accurate results to help you optimize your systems.

In this guide, you’ll learn exactly how to use the tool, understand the simple formula behind it, and explore practical examples. We also cover helpful information about brushless motor performance and provide answers to 20 frequently asked questions to ensure you have everything you need.

How to Use the Brushless Motor Power Calculator

Using the Brushless Motor Power Calculator is incredibly simple and straightforward. Here’s a step-by-step guide:

Enter Output Power (Watts):
In the first input box, type the motor’s output power in watts. This is the amount of useful mechanical power that the motor delivers.
Enter Efficiency (%):
In the second input box, input the motor’s efficiency as a percentage. Efficiency represents how effectively the motor converts electrical energy into mechanical energy.

Click on Calculate:
Press the “Calculate” button.
View the Result:
Instantly, the tool will display the calculated input power in watts. This is the amount of electrical power the motor actually consumes.

Formula Used in the Brushless Motor Power Calculator

The formula behind the tool is straightforward and easy to understand:

Input Power (watts) = Output Power (watts) ÷ (Efficiency ÷ 100)

In simple words:

First, divide the efficiency percentage by 100 to convert it into a decimal.

Then, divide the output power by this decimal value to get the input power.

Example:

Suppose your motor has:

Output Power = 300 watts

Efficiency = 85%

Using the formula:

Input Power = 300 ÷ (85 ÷ 100)
Input Power = 300 ÷ 0.85
Input Power ≈ 352.94 watts

Thus, your motor’s input power would be approximately 352.94 watts.

Practical Example of Brushless Motor Power Calculation

Imagine you are setting up an electric drone with the following motor specifications:

The motor outputs 500 watts of mechanical power.

The motor efficiency is rated at 80%.

Step-by-Step Calculation:

Convert efficiency percentage into a decimal:
80% ÷ 100 = 0.80

Apply the formula:
Input Power = 500 ÷ 0.80
Input Power = 625 watts

Result:
Your motor requires 625 watts of electrical input to produce 500 watts of mechanical output.

This means 125 watts are lost primarily as heat and other inefficiencies, underlining the importance of selecting a high-efficiency motor when performance and battery life are critical.

Why Is Calculating Brushless Motor Input Power Important?

Design Accuracy:
Ensuring the power supply matches the motor’s input needs prevents underpowering or overpowering.
Battery Management:
In applications like drones and e-bikes, accurate input power calculation helps in battery selection, resulting in better performance and longer battery life.
Heat Management:
Understanding input power helps manage heat dissipation, ensuring longer motor life and system reliability.

Energy Efficiency:
By knowing the input power, you can optimize systems for higher energy efficiency, saving both cost and energy.

Additional Information About Brushless Motors

Higher Efficiency:
Brushless motors generally offer better efficiency than brushed motors, often achieving 80%-90% efficiency or higher.
Reduced Maintenance:
No brushes mean less wear and tear and longer motor lifespans.

Precise Control:
Brushless motors offer more precise speed and torque control, essential for robotics, drones, and automated systems.
Cost Factor:
Although more efficient, brushless motors tend to be more expensive than their brushed counterparts.
Importance of Cooling:
Even with high efficiency, brushless motors generate heat. Adequate cooling measures are crucial for optimal performance.

20 FAQs About Brushless Motor Power Calculator

Q1: What is output power in a brushless motor?
A1: It’s the mechanical power that the motor delivers, measured in watts.

Q2: What is input power in a brushless motor?
A2: It’s the total electrical power consumed by the motor to produce mechanical output.

Q3: How do I measure output power?
A3: Output power can be measured using a dynamometer or calculated using torque and rotational speed.

Q4: What is motor efficiency?
A4: Efficiency is the ratio of output power to input power, expressed as a percentage.

Q5: Why do I need to calculate input power?
A5: To ensure proper power supply selection and manage system efficiency.

Q6: Can efficiency be more than 100%?
A6: No, efficiency above 100% is not possible due to energy conservation laws.

Q7: What affects brushless motor efficiency?
A7: Load, design, temperature, and electrical losses impact efficiency.

Q8: Is a higher efficiency always better?
A8: Yes, higher efficiency means less energy wasted as heat.

Q9: Can I use this calculator for brushed motors?
A9: Yes, the formula applies to any motor type.

Q10: What unit should output power be in?
A10: Output power should always be entered in watts.

Q11: Does the calculator consider temperature effects?
A11: No, it assumes rated efficiency without environmental factors.

Q12: How accurate is the Brushless Motor Power Calculator?
A12: It’s highly accurate if correct output power and efficiency values are provided.

Q13: What happens if I input wrong values?
A13: The calculator will still compute, but the result will not reflect real motor behavior.

Q14: Can efficiency change over time?
A14: Yes, motor wear and environmental conditions can reduce efficiency over time.

Q15: What if I don’t know the efficiency?
A15: You can refer to the motor’s datasheet or estimate based on similar motor types.

Q16: How is motor heat related to input power?
A16: The difference between input and output power usually dissipates as heat.

Q17: Does input power affect battery life?
A17: Yes, higher input power demands more from the battery, reducing its lifespan.

Q18: Can I improve motor efficiency?
A18: Proper lubrication, cooling, and load management can help maintain efficiency.

Q19: Are brushless motors waterproof?
A19: Some are designed to be waterproof, but always check the manufacturer’s specifications.

Q20: Can I use this calculator for industrial motors?
A20: Absolutely, as long as you know the output power and efficiency, it works for all scales.

Final Thoughts

The Brushless Motor Power Calculator is an essential tool for engineers, hobbyists, and manufacturers looking to optimize motor-driven systems. By simply entering the motor’s output power and efficiency, you can instantly know the input power, helping in better design decisions, efficiency management, and system performance optimization.

Whether you are building a high-performance drone, an electric bike, or setting up an industrial application, accurate power calculation is the foundation of success. Use our easy-to-operate calculator today and unlock new levels of precision and efficiency in your projects!