Professional electrical engineering tools for cable sizing, load calculations, transformer sizing, and system design per NEC/IEC standards.
Cable size in mm² or AWG by current, derating and voltage drop (IEC, BS 7671 & NEC)
Build a panel schedule with demand load, auto cable size (Cu/Al), voltage drop, derating & breaker sizing (IEC & NEC)
Calculate load current from power and voltage
DOL and star-delta contactors, overload setting and motor FLC table
Copper or aluminium phase, neutral and earth busbar sizes
Solar array kWp, number of panels, battery and inverter size
Calculate residential electrical load per NEC
Size transformers based on connected load
Advanced transformer sizing with loading margin, ambient derating & ANSI/IEC ratings
Minimum tray width per NEC 392.22 or percent fill (IEC practice)
Minimum conduit size and % fill for EMT, IMC, RMC & PVC per NEC Chapter 9
Calculate voltage drop in electrical cables
Calculate fault current for equipment rating
Calculate lighting levels and fixture requirements
Size standby generators for buildings
Diesel L/h at any load, day tank and main storage size
Calculate PF, kVA, kVAR & phase angle from kW, voltage and current — single & three phase with calculation steps
Capacitor bank kVAR to raise power factor, with kVA and current before and after
Design earthing systems per IEEE 80
Full kW power calculator for single-phase & three-phase systems
Convert kW to current (amps) for 1φ and 3φ systems
Quick cable size recommendation from kW, voltage, PF, and length
Convert kW to BTU/hr for HVAC heat load calculations
Convert kW to horsepower (HP) with selectable HP type & efficiency
Convert kW to kVA and kVAR using power factor (PF) with steps & analysis
Select standard breaker rating from amps or kW with optional IEC/NEC verification
Decode capacitor color bands & printed codes (104, 473, 4R7) to pF/nF/µF with tolerance — plus reverse value-to-code mode
These calculators cover the everyday design checks on an electrical project, from the first load estimate to cable, breaker and transformer selection. Each tool shows its formula and calculation steps, so you can check the result instead of trusting a black box, and states the standard it follows: IEC 60364, BS 7671 or the NEC.
The Cable Size Calculator sizes copper or aluminium cable in mm² or AWG from current-carrying capacity, temperature and grouping derating, and voltage drop. Start from kW with the kW to Cable Size Calculator, check long runs with the Voltage Drop Calculator, and size the protective device with the Breaker Size Calculator.
Convert between kW, kVA, amps and horsepower, build a panel schedule with the Electrical Panel Load Calculator, and find power factor, kVA and kVAR with the Power Factor Calculator. To improve a low power factor, the Power Factor Correction Calculator sizes the capacitor bank.
Size transformers and standby generators, estimate short circuit current for equipment ratings, design earthing systems, and plan lighting levels in lux. Results are design estimates; final designs should be verified against the applicable code and manufacturer data.