VoltBook

75 always and forever free electrical calculators — now with VoltBook Pro: AI on every calculator and nameplate scanning.

VoltBook is the electrician's field toolbox: fast, accurate electrical calculators, searchable code references, and job documentation — built for the panel room, the lift, and the trench. All 75 calculators and every table are free and work fully offline, forever — no account required.

75 CALCULATORS, 14 CATEGORIES • Electrical basics — Ohm's law, AC power, power factor, energy cost • Conductors — voltage drop, ampacity, temperature and fill derating • Raceway — conduit fill and minimum size, with a custom cable library • Conduit and tube bending — offsets, saddles, stubs, kicks, segment bends • Motors, transformers, and VFDs — FLC, kVA, OCPD, overloads, V/Hz • Grounding and OCPD — EGC, GEC, continuous loads, breaker sizing • Fault current, instrumentation loops, PLC scaling, and unit conversions

Results show their NEC references, and you can switch between the 2020, 2023, and 2026 editions. Save any calculation to a project for later.

REFERENCE, WITHOUT THE FLIPPING Ampacity, conduit fill, grounding, and motor tables in a searchable format, plus a full electrical symbol library and step-by-step bending guides.

AI THAT KNOWS THE TRADE Every plan includes AI requests each month — no account, key, or setup needed. Describe the job in plain language and the AI Assistant runs the verified calculators for you. Ask AI on any calculator to explain results or draft field notes, and use the Nameplate Scanner to pull data straight off motor, transformer, and VFD nameplates.

VOLTBOOK PRO The calculators stay free forever. Pro unlocks the documentation workflow: • Unlimited projects and saved calculations • Material lists you can check off at the counter and send by text or email • Branded PDF calculation sheets and photo field reports • 500 AI requests a month (Free includes 5) • Bring your own OpenAI, Anthropic, Gemini, or OpenRouter API key for unlimited AI — usage billed by your provider, and your key never leaves your device

Pro is available as a monthly or annual subscription. Payment is charged to your Apple ID, and subscriptions renew automatically unless canceled at least 24 hours before the end of the period. Manage or cancel anytime in your App Store settings.

VoltBook is a professional aid — always verify results against the applicable code and local amendments before installation.

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