Free Electrical Calculators

Free Electrical Calculators
for Electricians

Standards-compliant calculators for electricians in NZ & Australia. Free, no signup required. Works on mobile.

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All calculations run in your browser. No account needed.

Cable Size Calculator

Ohm's Law Calculator

Formulas:

V = I × R (Ohm's Law)

P = V × I (Power)

P = I² × R

P = V² / R

Wire Size Converter

Three-Phase Power Calculator

Enter in watts

Common Loads:

  • • LED Light: 5-15W
  • • Fridge: 100-400W
  • • Heater: 1000-2400W
  • • AC Unit: 2000-5000W

More Specialised Calculators

Dedicated calculators for specific tasks with full SEO-optimised pages.