Electrical & Engineering Calculators

Ohm’s law, voltage drop, energy cost and wire sizing.

What one appliance costs to run per day, month and year.

Voltage, current, resistance and power from any two of them.

Volts lost along a run, the percentage drop, and whether it passes the 3% check.

Torque, force, volts or kW into horsepower, with quarter-mile estimates for scale.

Lumens to watts by bulb type, watts back to lumens, with room targets and lamp counts.

Real, apparent and reactive power plus the current, single or three phase.

Read a resistor from its colors, or find the colors for a resistance value.

Network, broadcast, host range and netmask from an IPv4 address and prefix.

AWG to diameter, mm², resistance and ampacity — or the nearest AWG for a metric cable.