Electrical Engineering Calculation Suite

Practical Calculations and Engineering Reference Tools

Calculate voltage drop, power, transformer capacity, motor current, conduit fill and electrical load schedules in one place.

Voltage drop calculator

Estimate line voltage drop using conductor resistance/reactance inputs.

System Voltage (V)Load current (A)One-way cable length (m)Conductor resistance (Ω/km)Reactance (Ω/km)Power factor

Enter values and calculate.

Power factor & kW / kVA

Convert real, apparent and reactive power for single- or three-phase systems.

System Voltage (V)Current (A)Power factor (0–1)Known value Known power (kW or kVA)

Enter values and calculate.

Transformer sizing

Estimate required kVA from connected load and a design margin.

Connected load (kW)Power factorDesign margin (%)Expected demand factor (%)System voltage (V)

Enter values and calculate.

Cable selection reference

Indicative copper conductor reference values. Confirm installation-specific ampacity and derating.

Area (mm²)	Approx. R at 20°C (Ω/km)	Indicative current range (A)*	Typical use guide
1.5	12.1	10–18	Lighting / small circuits
2.5	7.41	16–27	General socket circuits
4	4.61	25–37	Small power circuits
6	3.08	32–47	Higher-load branch circuits
10	1.83	43–65	Submains / larger circuits
16	1.15	57–87	Distribution feeders
25	0.727	75–110	Distribution feeders
35	0.524	90–135	Large feeders
50	0.387	110–165	Large feeders
70	0.268	140–210	Large feeders
95	0.193	170–255	Large feeders
120	0.153	195–290	Large feeders

*Current ranges are illustrative only and vary significantly with insulation, ambient temperature, installation method, grouping, soil conditions and local code. Resistance values are approximate copper values at 20°C.

Lookup conductor area (mm²)One-way length (m)Load current (A)System voltage (V)

Select a conductor and calculate.

Motor current & power

Estimate input power and line current from motor output power and efficiency.

System Motor output power (kW)Voltage (V)Efficiency (%)Power factor

Enter values and calculate.

Conduit fill estimator

Calculate approximate fill percentage using internal conduit diameter and cable outside diameter.

Conduit internal diameter (mm)Cable outside diameter (mm)Number of cablesTarget fill limit (%)

Enter values and calculate.

Electrical load schedule

Add loads to estimate connected kW, kVA and design current. Values are preliminary.

Load nameQuantityUnit load (W)Power factorDemand factor (%)System voltage (V)Phase

Load	Qty	Connected (kW)	Demand (kW)	PF	Action
No loads added yet.
Total		0.00 kW	0.00 kW	0.00 kVA

Add one or more loads to build a schedule.

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Important: Results and reference tables are preliminary estimates, not a substitute for applicable electrical codes, manufacturer data, fault-level/protection coordination, thermal calculations, or review by a qualified electrical engineer. Cable ampacity and conduit fill requirements depend on local standards and installation conditions.