Skip to content
Electrician1001
Sign in Open calculators

Electrical Box Fill Calculator

NEC 314.16 box fill from conductor count, devices, and box volume.

Inputs

Inputs and assumptions

Largest gauge present. 12 AWG is 6530; 14 AWG 4110; 10 AWG 10380.

Count each conductor once.

Each device counts as two of the largest conductor.

All grounds together count as one largest conductor.

Marked inside the box.

Result

Fill used
15.75 cu in
Remaining volume
2.25 cu in
Screening tool. Verify against the NEC as adopted locally, the AHJ, and nameplate data before acting.

Related calculators

Related articles

01 Ohm’s Law Triangle: V, I, R in One Picture 02 Subpanel Sizing Basics: Load, Feeder, and Breaker Selection 03 Saddle Bends Explained: 3-Point and 4-Point Layouts

Workspace

Keep the assumptions with the result.

Save this calculation to return to the inputs, result, and report from your private workspace.

Sign in to save Create account

Sign in or create an account to save this calculation.