# NEC Box Fill Calc — Catch Overfilled Boxes Early

> Catch Overfilled Boxes Early (iPhone/iPad app by 光 杨.)

- Source: https://appshunter.io/ios/app/nec-box-fill-calc/id6767993285 (this page in markdown: same URL + `.md`)
- Developer: [光 杨](https://appshunter.io/developer/1891134953)
- Category: Utilities, Reference
- Price: Free with in-app purchases (on sale, was $2.99)
- Age rating: 4+
- Requires: iOS 17.0 · 2 MB
- Languages: American English
- Released: 2026-05-12
- Data updated: 2026-09-02
- User reviews in markdown: https://appshunter.io/ios/app/nec-box-fill-calc/id6767993285/reviews.md

## What is NEC Box Fill Calc?

NEC Box Fill Calc gives electricians a complete NEC 314.16(B) single-box field check at no charge. When a job spans multiple boxes, the existing Rough-In Schedule keeps labels and corrections together for a shareable handoff.

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 the Rough-In Box Schedule once to:
- Name the current project and label each box or room
- Collect up to 30 completed box checks on device
- See project totals for passing and overfilled boxes
- Put every required correction first, including overage, current box, and recommended replacement
- Reload any scheduled check into the free calculator
- Share or export one complete plain-text schedule
- 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.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Inspection Cards Lifetime Unlock | $7.99 | one-time |



## Version history (last 4 releases)

### 1.3 — 2026-09-02

Inspection Cards is now an exception-first Rough-In Box Schedule. Label up to 30 completed checks, see project totals and required corrections first, reload any box, and share or export one complete schedule. Full single-box results remain free.

### 1.2 — 2026-07-07

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.

### 1.1 — 2026-06-05

Updated App Store screenshots and product page visuals. App functionality is unchanged.

### 1.0 — 2026-05-13

No release notes.

## More apps by 光 杨

- [ConcretePour Pro](https://appshunter.io/ios/app/concretepour-pro/id6761770433)
- [Roofing Cost Estimator](https://appshunter.io/ios/app/roofing-cost-estimator/id6761807843)
- [Cut Optimizer Pocket](https://appshunter.io/ios/app/cut-optimizer-pocket/id6761807889)
- [KitchenBatch Pro](https://appshunter.io/ios/app/kitchenbatch-pro/id6761807896)
- [Tile Layout Pocket](https://appshunter.io/ios/app/tile-layout-pocket/id6761807981)
- [TipSmart Splitter](https://appshunter.io/ios/app/tipsmart-splitter/id6761808040)

All apps by 光 杨: https://appshunter.io/developer/1891134953

## Related topics

[electrical box fill calculator](https://appshunter.io/ios/topics/electrical-box-fill-calculator) · [breaker box](https://appshunter.io/ios/topics/breaker-box)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-02.*