Ampwise: Electrical Calc Pro

Ampwise is the electrical calculator that opens straight to the keys, cites the NEC on every answer, and never asks for a subscription. Buy it once — own it for good. Built for electricians, estimators, and engineers who are tired of paying monthly for tools that used to cost a one-time fee — and tired of digging through the code book to double-check a number on the job. ━━ Why electricians switch to Ampwise ━━ • One-time purchase to unlock Pro. No subscription. No ads. Ever. • Every result shows its NEC article or table — trust it on the job and in front of an inspector. • Works 100% offline. No signal, no account, no tracking. • Three tools in one app: a full scientific calculator, electrical calculators, and browsable NEC reference tables. • Fast and clean — opens to the keypad, no clutter, no pop-ups. ━━ Free — calculator, electrical math & reference ━━ • Full scientific calculator — trig, logs, powers, roots, π, e, DEG/RAD/GRAD • Voltage drop calculator — 1-phase & 3-phase, copper or aluminum, with the minimum conductor size to stay within 3% • Wire size / ampacity — NEC Table 310.16, 60/75/90 °C, plus next standard breaker (240.6) • Ohm's law — solve V, I, R, or P from any two • Power & current — single- and three-phase, with power factor • Series & parallel resistance • NEC ampacity reference table (Table 310.16) ━━ Pro electrical calculators — one-time unlock ━━ • Conduit fill — NEC Chapter 9, EMT with THHN/THWN-2, 40% fill • Box fill — NEC 314.16 volume allowances • Motor FLC & sizing — Tables 430.250 / 430.248, 125% conductor, 250% inverse-time breaker • Transformer sizing — primary & secondary full-load amps • Conductor derating — ambient temperature + bundling adjustment • Power-factor correction — capacitor kVAR sizing • Equipment ground / EGC — NEC Table 250.122 • Fault current — transformer infinite-bus + point-to-point down a feeder • Service / feeder load — NEC 220 dwelling standard method • kVA / kW / PF power triangle • 6 more NEC reference tables — conduit area, THHN areas, motor FLC, box fill, equipment ground, breaker sizes • Auto wire-size suggestion on the voltage-drop calculator • Save any calculation and export a clean PDF to send to a client or inspector ━━ Made for ━━ • Electricians and apprentices sizing conductors and conduit • Estimators and PMs checking voltage drop on long runs • Electrical engineers and designers doing fast field checks • Anyone studying for the journeyman or master electrician exam ━━ Buy once. Own it forever. ━━ No monthly fee. No "renew to keep your tools." One purchase unlocks every Pro calculator — and every Pro calculator we add in future updates. ━━ Important ━━ Ampwise is a professional aid, not a substitute for the National Electrical Code or a licensed engineer's judgment. Always verify against the current adopted code and local amendments. NEC® is a registered trademark of the NFPA; Ampwise is not affiliated with or endorsed by the NFPA.