Free Electrical Calculators

Free Electrical Calculators
for Electricians

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

Electrical Calculators· 11 tools

Each calculator opens on its own page — bookmark the ones you use most.

Cable Size Calculator

Size cables by load current and run length. AS/NZS 3000 and BS 7671 compliant.

AS/NZS 3000BS 7671Cable Sizing
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Ohm's Law Calculator

Solve for voltage, current, resistance or power from any two known values.

V=IRResistancePower
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Wire Size Converter

Convert wire sizes between mm², AWG and SWG. Quick reference for multi-standard work.

mm²AWGSWG
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Three-Phase Power Calculator

Calculate kVA, kW, current and power factor for three-phase loads.

Three-PhasekVAPower Factor
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EV Charger Load Calculator

Check if your panel can handle an EV charger. Panel utilisation, recommended breaker, cable size.

EVPanel Check
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Conduit Fill Calculator

Calculate how many cables fit in a conduit. PVC and steel conduit, TPS and single-core cables.

ConduitAS/NZS 3000
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Motor FLC Calculator

Motor full load current, recommended breaker, cable size, and overload settings.

MotorFLC
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Generator Sizing Calculator

Size a generator based on your electrical loads. Supports motor starting surge and demand factor.

GeneratorkVA
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Voltage Drop Calculator

Calculate voltage drop for any cable run. Copper and aluminium, single and three phase.

Voltage DropCable
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Energy Cost Calculator

Calculate how much an appliance costs to run. Daily, monthly, and annual costs.

EnergyCost
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Business Profit Calculator

Calculate your electrical business profitability based on jobs, rates, and overhead.

BusinessProfit
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