NEC Box & Conduit Calc

NEC Box & Conduit Calc is the most accurate way to calculate box fill, conduit fill, and wire volume according to the NEC (National Electrical Code).
Built for electricians, electrical contractors, engineers, inspectors, and students — this app provides instant, reliable fill calculations that save time on every job.

Key Features

• Box Fill Calculator
– Supports device counts, equipment grounding, internal clamps
– Includes all common box sizes and types
– NEC-compliant volume calculations
– Instant results with clear breakdowns

• Conduit Fill Calculator
– Supports EMT, PVC, RMC, IMC & more
– Choose multiple conductor sizes per conduit
– NEC-based fill percentages
– Quickly see pass/fail results

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

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

Perfect For

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