Engineering calculators & tools

Size a variable-frequency drive from motor kW, voltage, service factor and load duty type.

Estimate FLA from motor kW or HP, line voltage, power factor and efficiency — for sizing contactors and drives.

Estimate three-phase motor full-load current from kW, voltage, efficiency and power factor — with a NEC 430.250 reference table.

Convert motor kW or HP to full-load current for three-phase, single-phase and DC motors.

Convert motor power (kW or HP) and speed (RPM) to rated torque — or find the power for a target torque.

Compare starting current and torque across DOL, star-delta, soft starter and VFD (NEC 430).

Size the branch circuit breaker, fuse and overload for a three-phase motor (NEC 430).

Size the thermal overload relay for a three-phase motor from FLA and starting duty.

Check winding temperature against insulation class limits (A/E/B/F/H) from ambient and measured rise.

Compute slip between synchronous and actual speed — or find the speed at a target slip.

Convert motor synchronous speed between frequency (Hz) and RPM from the pole count — and read actual speed from slip.

Solve three-phase kW, kVA and line current from voltage, current and power factor.

Convert motor power between kilowatts and horsepower (imperial and metric) instantly.

Size a three-phase transformer from load kW, power factor and growth margin, with next-standard-size output.

Estimate available fault current at a transformer secondary (IEC 60909) for breaker interrupting rating checks.

Size the capacitor bank to improve power factor from any PF to a target — kVAR, capacitance and current.

Size the input line reactor for a variable-frequency drive from motor power and system impedance.

Size the dynamic brake resistor for a VFD from motor power, inertia and stop time.

Select a CT primary rating from load current and secondary (1A/5A), read the ratio and actual secondary current.

Convert loop current to an engineering value (and back) from sensor minimum / maximum scaling.

Convert a 0-10V analog signal to an engineering value (and back) from sensor minimum / maximum scaling.

Convert a 4-20mA or 0-10V sensor signal into its engineering value — and back.

Convert between PT100 resistance and temperature per IEC 60751 (Callendar–Van Dusen), both directions.

Convert temperature between Celsius, Fahrenheit and Kelvin instantly.

Tune a PID loop with Ziegler-Nichols or Cohen-Coon rules and read Kp, Ki and Kd.

Size an electric heater from mass, temperature rise and heating time for air, water or oil.

Calculate push and pull force from supply pressure (bar / MPa / psi), bore and rod diameter.

Estimate free-air consumption of a pneumatic cylinder for compressor and FRL sizing.

Convert pressure between PSI, bar, MPa, kPa, Pa and atmosphere in a single step.

Estimate hydraulic and shaft power for a pump from flow, head and efficiency.

Estimate the motor power for a belt conveyor from belt speed, load mass, length and friction.

Find output speed and torque from motor speed, gearbox ratio and efficiency, with standard ratio selection.

Decode two Modbus registers as a 32-bit IEEE 754 float in big- or little-endian order.

Convert between stepper shaft speed (RPM) and pulse frequency (Hz) with steps/rev and microstepping.

Convert motor power between kW, HP and kVA — and read line current for single- or three-phase.