Ampwise

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.