NEC Box & Conduit Calc

NEC-based conduit fill, box fill & sizing in seconds. Now with a cleaner, faster experience. Go Pro for unlimited calculations — no ads, ever.

NEC Box & Conduit Calc is the fastest, most accurate way to calculate box fill, conduit fill, required conduit size, and wire volume — all to the NEC (National Electrical Code).

Built for electricians, contractors, engineers, inspectors, and apprentices, it delivers instant, code-compliant results that save time on every job — right from your pocket, even offline.

Key Features

• Box Fill Calculator – Device counts, equipment grounding, internal clamps – All common box sizes and types – NEC-compliant volume with clear breakdowns

• Conduit Fill Calculator – EMT, PVC, RMC, IMC & more – Multiple conductor sizes per conduit – NEC fill percentages with instant pass/fail

• Required Conduit Size – Enter your conductors, get the correct conduit size instantly – See the next size up and down

• NEC Reference Tables – Chapter 9 Tables 1, 4 & 5 at your fingertips – Browse every NEC box and conduit size

• Accurate Wire Volume Data – Built-in AWG volume reference for field, shop, and inspection

• Professional PDF Reports – Export clean, shareable reports for your records or the inspector

• Clean, Simple Interface – Designed for electricians under time pressure – Easy to use with gloves – Works fully offline

Perfect For • Electricians • Electrical contractors • Students & apprentices • Inspectors • Engineers & designers

Download now and get code-compliant fill calculations in seconds — on every job.