Box Fill Calculator

Find the minimum electrical box volume (NEC).

Required box volume (in³) 16

Formula: box volume = conductor count × volume per conductor

Step-by-step with your numbers:

1. Values used:

2. Number of conductors = 8

3. Volume per conductor = 2

5. Required box volume = Number of conductors x Volume per conductor = 8 x 2 = 16in³

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Estimate the electrical box size (in³) needed for a given number of conductors.

The math behind it

required box volume = conductor count × the volume allowance per conductor (NEC).

8 × 14 AWG → 16 in³ box.

Devices?

Add 4× the conductor volume for each yoke/strap.