Practical field tools

Industrial electrical calculators

These browser-only calculators show an estimate using the values you enter. They do not save inputs or replace a qualified engineer, equipment manual or site safety procedure.

Three-phase power estimate

Estimate active power from line voltage, line current and power factor.

Line voltage (V)

Line current (A)

Power factor (0–1)

Enter values to calculate.

P ≈ √3 × V × I × power factor. Result is kW.

Motor current estimate

Estimate full-load current from motor power, voltage, efficiency and power factor.

Motor power (kW)

Line voltage (V)

Efficiency (0–1)

Power factor (0–1)

Enter values to calculate.

I ≈ P ÷ (√3 × V × efficiency × power factor).

Voltage drop estimate

Estimate a simple three-phase voltage drop from current, one-way length and cable resistance.

Current (A)

One-way length (m)

Conductor resistance (Ω/km)

Enter values to calculate.

ΔV ≈ √3 × I × R × length(km). Check the cable standard and installation method.

How to use these results: Treat them as a first estimate for discussion. Confirm cable data, system connection, motor duty, ambient conditions, protection settings and local requirements before selecting or commissioning equipment. If a result looks unexpected, stop and check the inputs rather than increasing a setting.

Why the assumptions matter

A calculator is useful when it makes the assumptions visible. Three-phase formulas depend on the system and whether values are line or phase values. Motor current depends on efficiency and power factor. Voltage drop depends on conductor temperature, reactance, installation method and allowable limit. Read the related three-phase guide and measurement guide before applying a result.