Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Speed Constant Rpm Per Volt (rpm/V)

Required number input.

Voltage Volts (V)

Required number input.

Ideal no-load rotational speed from motor speed constant and applied voltage; ignores friction and no-load current drop. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Speed Rpm (rpm)

The resulting speed rpm returned as a number.

• Motor constants, current, torque, speed, reactive power, and propeller thrust depend on winding temperature, controller, supply sag, losses, saturation, load curve, airflow, and operating point. Nameplate constants and ideal propeller laws need test data for final sizing.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Motor Torque Speed Curve

  Linear permanent-magnet DC motor torque at a specified speed using stall torque and ideal no-load speed.

• Battery Internal Impedance

  Estimate DC battery internal resistance from the voltage drop between two load-current operating points measured over a short interval.

• Battery Life Calculator

  Estimate battery runtime from rated charge capacity and constant load current: hours = mAh / mA. Real-world derating (Peukert effect, temperature, cutoff voltage) is not modeled.