NEC box fill calculator. Junction box volume per Article 314.16. Offline.
About Box Fill NEC 314 Calculator
Box Fill NEC 314 Calculator is a tools app developed by ZkDev.
Download Statistics
Box Fill NEC 314 Calculator has been downloaded 420 times. In the last 30 days, the app was downloaded 77 times.
User Ratings
The app has no ratings yet.
App Information
Box Fill NEC 314 Calculator is FREE to download. The APK download size is 20.72 MB. The latest version available is 1.0.9. The last update was on July 23, 2026.
Technical Requirements
The app has a content rating of Everyone. The app has been available on Google Play March 2026.
Description
NEC box fill calculator for electricians, apprentices, and electrical engineers. Your go-to junction box calculator for outlet box fill and device box volume calculations per NEC 314. Calculate box fill volumes instantly using official NEC 2023 Article 314.16 data (Tables 314.16(A) and 314.16(B)) with support for all standard metal box types. No internet required - works 100% offline on the job site.
Whether you're verifying outlet box fill for a device box, calculating junction box volumes, or checking if your conductor fill exceeds NEC limits, this electrical box calculator gives you accurate results in seconds. Use it as your portable box fill chart reference for residential and commercial installations.
FEATURES: • All 24 standard metal box sizes from Table 314.16(A): Device 3x2 and 4x2-1/8 (handy box), Round/Octagonal, Square 4", Square 4-11/16", Masonry, FS, FD • Custom volume entry for non-standard boxes • Conductor sizes: 18 AWG to 6 AWG per Table 314.16(B) • Internal cable clamps, fixture studs, and hickeys • Multi-gang device fill calculation • Equipment grounding conductors (EGC) with NEC 2023 rules • Isolated grounding conductors - separate allowance • Visual PASS/FAIL indicator with fill percentage • Shows minimum box volume needed when over-filled • Suggests a standard box that will pass
PRO FEATURES (one-time purchase): • No ads • Save calculation history • Export calculations as PDF reports • Dark theme support
BUILT FOR THE JOB SITE: This app is designed by electricians, for electricians. The interface is clean, fast, and works with one hand. Add conductors, check your fill, and move on - no complicated menus or unnecessary features.
ACCURATE NEC DATA: All box volumes are sourced from NEC 2023 Table 314.16(A). Conductor volume allowances follow Table 314.16(B) exactly. Fill rules follow Article 314.16 for conductors, clamps, support fittings, devices, and grounding conductors. Always verify calculations against the official NEC code book before installation.
NEC 314.16 FILL RULES: • Each conductor: volume from Table 314.16(B) based on AWG size • Internal clamps: 1× largest conductor volume (all clamps combined) • Support fittings: 1× largest conductor per fitting type • Devices: 2× largest conductor per gang • EGC (≤4): 1× largest EGC volume • EGC (>4, NEC 2023): 1/4 allowance per additional conductor • Isolated grounds: counted separately
PERFECT FOR: • Licensed electricians doing box fill calculations daily • Electrical apprentices studying for journeyman exams • Electrical engineers and designers • Electrical contractors bidding residential and commercial jobs • NEC code exam preparation (Journeyman & Master) • Anyone who needs a fast, accurate junction box calculator
OFFLINE & PRIVACY: • Works 100% offline - no internet needed • No account required • No data collection • Your calculations stay on your device
Simplify your box fill calculations on the job site.
Recent changes: • NEC Article 314.16 box fill calculations • All standard metal box types and sizes • Conductor, clamp, device, and EGC volume tracking • Cross-promotion: discover our other NEC calculator apps • In-app review for easier rating • PDF export and calculation history • Bug fixes and performance improvements
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