Free Electrical
Calculators
25 calculators built for Australian electricians. Cable sizing, voltage drop, maximum demand and more — always free, always up-to-date.
25
Free Calculators
2025
Standard Compliant
$0
No Paywall
PWA
Works Offline
All Calculators
25 tools covering everything from cable sizing to arc flash analysis. All free, all AS/NZS compliant.
Core Calculations
Essential tools for every jobCable Sizing
AS/NZS 3008.1.1:2025
Auto-size cables for current rating, voltage drop, and earth fault loop impedance.
Voltage Drop
AS/NZS 3008.1.1:2025
Check voltage drop compliance for any cable size, length, and load.
Maximum Demand
AS/NZS 3000:2018
Calculate maximum demand using Tables C1 and C2 for residential and commercial.
Conduit Fill
AS 2053 + AS/NZS 3000
Check cable fill percentage and find minimum conduit size for your cable run.
Earth Conductor
AS/NZS 3000:2018
Size earth conductors using Table 5.1 or the adiabatic equation.
Circuit Breaker
AS/NZS 3000:2018
Select the correct breaker rating and curve for any circuit.
Solar & EV
Renewables and electric vehiclesSolar PV Sizing
AS/NZS 4777.2 + 5033
Full solar system sizing — panels, inverter, yield, payback, and export limits.
Voltage Rise
AS/NZS 4777.1:2024
Solar PV voltage rise and export limit calculation for grid-connected inverters.
EV Charger Sizing
AS/NZS 3000 + 3001.1
Cable and breaker sizing for EV charger installations.
Motors & Power
Industrial and commercialMotor Calculator
AS/NZS 3000 + 1359
Full load current, cable sizing, breaker selection, and starter sizing.
Three-Phase Power
Utility
Convert between voltage, current, and power for star and delta systems.
Full Load Current
AS/NZS 3000 + 3008
Calculate FLC for motors, transformers, heaters, and lighting.
Motor Speed
IEC 60034
Synchronous and actual speed for any pole count and frequency.
Motor Torque
AS/NZS 1359 + IEC 60034
Full load, starting, breakdown, and pull-up torque calculations.
Power Factor
AS/NZS 61000.3.100
Calculate capacitor bank size to correct power factor.
Transformers & Generators
Sizing and fault analysisTransformer Sizing
AS 2374 / AS 60076
Size transformers with demand factors, growth planning, and protection.
Transformer Fault
IEC 60909
Three-phase and single-phase fault current at transformer secondary.
Generator Sizing
AS/NZS 3010:2014
Size generators for motor starting, derating, and fuel consumption.
Protection & Safety
Safety-critical calculationsArc Flash
IEEE 1584:2018
Incident energy, arc flash boundary, and PPE category.
RCD Selection
AS/NZS 3000:2018
Select the right RCD type and sensitivity. Includes NZ Type A mandate.
IDMT Relay
IEC 60255
Operating time for all 5 IEC inverse curves — SI, VI, EI, LTI, DT.
Earthing System
AS/NZS 3000 S5
Design earth electrodes with touch/step voltage checks.
Emergency Lighting
AS/NZS 2293.1
Luminaire count, exit signs, spacing, and battery sizing.
Why electricians switch to ElecCalc
See how we compare to the alternatives.
| Feature | jCalc | ElecAS | ElecCalc |
|---|---|---|---|
| Price | A$265/year | Free | 100% Free |
| AS/NZS 3008:2025 | 2017 only | Unclear | Day one |
| Calculators | 17 | ~8 | 25 |
| Works on mobile | Desktop only | Partial | Mobile-first |
| Works offline | No | No | PWA |
| PDF export | Paid only | No | Free |
| No login needed | Yes | Yes | Yes |
Ready to calculate?
Start with Cable Sizing — the most popular calculator for Australian electricians.
Open Cable Sizing Calculator