Electrician Calc Pro

Electrician Calc Pro is a NEC 2026 reference calculator built for licensed electricians, electrical contractors, and apprentices who need fast, transparent answers in the field. SEE EVERY STEP Every calculation shows the formula, the substitution, and the result — not just a number. You can verify the work against the NEC and hand a step-by-step report to an inspector or client. SIX CALCULATORS, ONE APP • Voltage Drop — exact & K-factor methods, 1-phase / 3-phase / DC, temperature-corrected resistance from NEC Chapter 9 Table 8 • Wire Size — NEC Table 310.16 ampacity with 240.4(D) small-conductor limits • Conduit Fill — Chapter 9 Tables 1 & 4, Annex C, 13 raceway types (EMT, RMC, PVC, and more) • Box Fill — NEC 314.16(B) volume allowances for conductors, devices, and clamps • Ohm's Law — solve V, I, R, or P from any two knowns • Unit Convert — AWG ↔ mm², circular mils, diameter, °C ↔ °F OFFLINE & PRIVATE No internet connection required — perfect for job sites. All data stays on your device. No accounts, no analytics, no ads. Your calculation history never leaves your phone. FIELD-FIRST DESIGN Large tap targets for gloved hands. Haptic feedback on results. Dark mode by default for bright outdoor screens. One-thumb operation throughout. HISTORY & FAVORITES Save calculations, mark the ones you reuse as favorites, and reopen any of them later with full step-by-step detail. Export any calculation as a clean PDF report for permits, records, or your client. ONE-TIME UNLOCK Voltage Drop, Wire Size, Conduit Fill, and Box Fill are Pro features — a single $9.99 purchase unlocks all four forever. No subscription, no recurring charge. Ohm's Law and Unit Convert are free. Ohm's Law and Unit Convert are available at no cost so you can try the experience before buying. NEC® and National Electrical Code® are registered trademarks of the National Fire Protection Association. This app is an independent reference tool and is not affiliated with or endorsed by the NFPA. Calculations are estimates for preliminary field use and education — always verify against the NEC edition adopted by your local Authority Having Jurisdiction (AHJ).