Box Fill Calc NEC
NEC Art.314 Box Volume
About
Instantly calculate electrical box fill volumes using official NEC 2023 data. This offline tool helps electricians and apprentices determine box capacity for conductors, clamps, and devices, providing a clear pass/fail indicator and suggesting appropriate box sizes.
What's New in Box Fill Calc NEC
1.0.9
June 10, 2026
What's new: • Complete NEC Table 314.16(A) catalog — added 4x2-1/8 device boxes (handy box): 10.3, 13.0, 14.5 cu.in. All 24 standard metal box sizes covered • Fixed EGC fill per NEC 2023 314.16(B)(5): each EGC beyond 4 now adds a 1/4 volume allowance Thanks for using ElecTools! Send feedback to support@tradetools.dev.
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FAQ
Does Box Fill Calc NEC have ads?
Yes, Box Fill Calc NEC contains advertisements. Users can remove ads and access additional features like saving history and PDF export by purchasing the Pro version.
What NEC code version does Box Fill Calc NEC use?
Box Fill Calc NEC utilizes the official NEC 2023 Article 314.16 data for its calculations, including Tables 314.16(A) and 314.16(B).
Can I use Box Fill Calc NEC without an internet connection?
Yes, Box Fill Calc NEC works 100% offline. This feature is ideal for use on job sites where internet access may be limited or unavailable.
What types of electrical components can Box Fill Calc NEC calculate for?
Box Fill Calc NEC calculates for standard metal box sizes, custom volumes, various conductor sizes (18 AWG to 6 AWG), internal cable clamps, fixture studs, hickeys, multi-gang devices, and equipment grounding conductors.
How does Box Fill Calc NEC indicate if a box is overfilled?
The app provides a visual PASS/FAIL indicator that shows the fill percentage. If a box is over-filled, it will also suggest the minimum box volume needed and recommend a standard box that will pass.
What devices is Box Fill Calc NEC available on?
Box Fill Calc NEC is available for iPhone, iPad, and iPod devices.
How often is Box Fill Calc NEC updated?
The latest version, 1.0.9, was released on June 10, 2026. Updates typically address code changes and app improvements.
Is Box Fill Calc NEC suitable for exam preparation?
Yes, Box Fill Calc NEC is perfect for NEC code exam preparation, including Journeyman & Master electrician exams, by helping users practice and understand fill calculations.
