Motor Performance Calculator

The charts throughout our website show the performance at a particular voltage for each motor. You can use the calculator below to generate a custom chart for any of our motors at any voltage. You can also use this utility to estimate the performance of any brushed or brushless permanent magnet DC motor if you know the Kv, the resistance, and the no-load current.

Click on any standard AmpFlow motor listed below, and the parameters will be loaded automatically. Then you can adjust the voltage or the reduction ratio and instantly see the calculated performance.

Use a reduction ratio of 1.0 if the motor is connected directly to the load. If you are using one of our speed reducers, enter the reduction ratio, along with the gearhead efficiency. AmpFlow chain reduction ratios are 4.38, 8.26, 15.93, 26.64. The efficiency for the chain reducers is 90%. The 1:4 and 1:8 planetary reducers are at 85%, and the 1:16 and 1:32 planetary reducers are 80% efficient. The best design practice is to use the highest reduction ratio possible while still getting the required top speed.

AmpFlow motors can produce very high torque at high current. This is fine for short-term or momentary bursts when accelerating, but for longer duty cycles, try to stay on the left side of the peak of the green efficiency curve to keep heat generation low. Please contact us if you have any questions regarding any of these calculators.

If you are designing a robot, scroll down for a handy robot performance calculator.

V A %

Click below to load the chart for standard AmpFlow motors.

Motor Kv Armature Resistance No Load Current Voltage
E30-400-12 549.20 0.030 5.5 12
E30-150-12 504.40 0.069 4.4 12
E30-400-24 240.35 0.089 3.2 24
E30-150-24 237.26 0.190 2.1 24
E30-400-48 121.84 0.284 1.4 48
E30-150-48 118.41 0.708 1.0 48

Motor Kv Armature Resistance No Load Current Voltage
A28-400-24 205.40 0.044 4.4 24
A28-150-24 256.90 0.064 4.4 24
A28-400-48 134.15 0.066 4.4 48
A28-150-48 155.50 0.165 2.5 48
F30-400 188.74 0.076 2.1 24
F30-150 289.95 0.081 2.5 24

Motor Kv Armature Resistance No Load Current Voltage
A15-100-24 438.00 0.78 1.6 24
A15-100-48 182.00 2.0 0.6 48
A23-150 269.00 0.210 1.0 24
F24-150-12 482.34 0.156 2.5 12
F24-150-24 209.80 0.585 1.1 24
A40-300 167.89 0.050 3.5 24

Robot Performance Calculator

This calculator uses the motor information from the above performance chart. If you haven't already done so, please enter your motor parameters, or click on a standard AmpFlow motor above. Adjust the wheel diameter and the reduction ratio to get the required top speed.




The calculator will show the power required for operating at a steady speed on level ground, accelerating on level ground, and climbing an incline at a steady speed.

Check the Steady State torque on the chart to make sure it is on the left of the peak of the green efficiency curve. It is okay to go to the right of the efficiency peak when accelerating or climbing an incline.


Steady State (Level)

(Per Motor)

Accelerating (Level)

(Per Motor)

Steady State (Incline)

(Per Motor)


*Wheelspin likely at higher than 0.8 g.

(Wheelspin is not accounted for in the results.)



Most robots will have a rolling resistance similar to a car on concrete. Adjust the slider below if your robot is intended for off-road use. Note that the gear train efficiency has already been taken into consideration above. This slider is for the added drag from rolling resistance only. Aerodynamic drag is not accounted for in this simulation.

Train Wheel on Rail Car on Concrete Car on Loose Gravel Car on Loose Sand

Motor Power Calculator

Use this tool to calculate the required motor power from the torque and the speed.

Power from Torque and Speed