Box fill calculator
Box type
Box size
Bare or green, all together
Fixture studs or hickeys
Cable clamps inside
Result
18 in³ needed
Fits: the 3 × 2 × 3½ in. device box holds 18 in³.
- Box volume
- 18 in³
- Needed
- 18 in³
- Room left
- 0 in³
How it is calculated
- 12 AWG conductors: 4 × 2.25 in³ = 9 in³
- Internal cable clamps: 1 × 2.25 in³ = 2.25 in³
- Devices (2 each): 1 × 4.5 in³ = 4.5 in³
- Grounding conductors (2, counted together): 1 × 2.25 in³ = 2.25 in³