Calculators for electricians

Check the voltage drop on a copper cable run against the UK wiring regulations' 3% and 5% limits, with the longest run and smallest cable that pass.

Find voltage, current or resistance from the other two using Ohm's law, or a heater element's resistance from its watts. Shows the power.

Convert watts to amps, or amps to watts, for DC, single-phase or three-phase AC, with power factor. Shows the working.