NEC Box Fill Calc
NEC Box Fill in Seconds
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
Catch an overfilled box before rough-in inspection fails. Free field checks stay open. Unlock saved inspection cards, sharing, export, and restore once.
Catch an overfilled box before rough-in inspection fails.
NEC Box Fill Calc helps electricians run a fast NEC 314.16(B) field check on site, see exactly where the volume went, and spot the smallest listed box that fits before rework starts.
Free field check:
- Add conductors by gauge from 18 AWG through 6 AWG
- Count grounding conductors, internal clamps, support fittings, and devices correctly
- See total fill, pass/fail status, line-by-line breakdown, and the smallest listed standard box that fits
- Switch between 20 standard box sizes or enter a custom marked volume
- Work fully offline with no account, ads, or subscription
Unlock Inspection Cards once to:
- Save inspection cards on device
- Pin important cards for repeat rough-in work
- Reload a saved card back into the free check workflow
- Share or export a plain-text inspection summary
- Restore lifetime access on another device
Built for electricians, apprentices, and foremen who want to avoid repulls, box swaps, and inspection-day surprises.
Important:
- Always verify the enclosure's marked volume and local requirements on site.
- This app is a practical field aid, not a substitute for code judgment or inspection approval.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Free core box fill checks now stay open. Added the one-time Inspection Cards unlock for saved cards, pin/load workflow, sharing, export, restore, and grandfathering for paid-era users.
The developer, 光 杨, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- 光 杨
- Size
- 1.3 MB
- Category
- Utilities
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Inspection Cards Lifetime Unlock $7.99
- Copyright
- © 2026 Guang Yang