Box Fill Calculator
Calculate electrical box fill requirements per NEC Article 314. Determines if your box is adequately sized for conductors and devices.
in
in
in
Conductor Counts
wires
Hot + neutral wires
wires
Bare or green wires
splices
devices
Each yoke counts as 2 conductors
clamps
Each clamp counts as 1 conductor
fittings
Each fitting counts as 1 conductor
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Box Fill Analysis
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Box Volume
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in³
Required Volume
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in³
Conductor Volume
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in³
Status
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NEC 314.16
Calculation Breakdown
Step-by-step box fill analysis
Box Fill Formulas
NEC 314.16 requirements
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Electrical Disclaimer: This calculator provides estimates for box fill based on NEC 314.16. Always consult the latest NEC code and a licensed electrician for proper electrical box sizing and installation.