Electrical Calculator: NEC

Electrical Calculator is a fast, offline toolkit for electricians, students and DIY pros - with no subscription and no ads. The core calculators are free forever. Unlock Pro once (no subscription, ever) for the full professional set. FREE - Ohm's Law: enter any two of volts, amps, ohms, watts - Energy cost: power, hours and rate to kWh and cost - Series and parallel resistance PRO (one-time) - Voltage drop: wire, load and length to drop, percent and end voltage - Wire size: smallest AWG for load and voltage drop - Ampacity: AWG to amps (NEC 310.16, 75C) with breaker limits - Conduit fill: EMT and THHN to percent fill - Box fill: conductors and devices to required volume (NEC 314.16) - Motor FLA: HP and voltage to full-load amps, conductor and breaker - Three-phase power and current, transformer kVA - Power factor correction, conduit bending, wire resistance, amps to kW/HP MORE - Works fully offline, no account, no tracking - Light and dark themes, English and Russian - Paperless tape: save and share your results Estimates are based on the NEC. Always verify against your local code and the authority having jurisdiction. This app is a tool, not a substitute for a licensed electrician.