Free Tools
Electrical calculators, no sign-up needed
Quick, practical tools for planning a wiring job or comparing running costs. Estimates only — always get a licensed electrician to confirm anything connected to your mains.
Wire & Cable Size Calculator
Find a suitable cable size for a given load, run length and voltage-drop limit.
Open calculatorOhm's Law Calculator
Solve for voltage, current, resistance and power from any two known values.
Open calculatorElectricity Running Cost Calculator
Estimate the daily, monthly and yearly cost of running an appliance.
Open calculatorMCB / Fuse Size Calculator
Get a recommended MCB rating for a given connected load.
Open calculator