BoxFill Calculator

Electrical Box Types & Sizes

Complete reference guide for electrical box types with volume specifications and dedicated fill calculators for each box size.

34

Box Types

24

Metal Boxes

10

PVC Boxes

Metal Electrical Boxes

4" Square x 1-1/4" Deep

4" x 4" x 1-1/4"

18 cu.in.Max 9 × 14AWG

4" Square x 1-1/2" Deep

4" x 4" x 1-1/2"

21 cu.in.Max 10 × 14AWG

4" Square x 2-1/8" Deep

4" x 4" x 2-1/8"

30.3 cu.in.Max 15 × 14AWG

4-11/16" Square x 1-1/4" Deep

4-11/16" x 4-11/16" x 1-1/4"

25.5 cu.in.Max 12 × 14AWG

4-11/16" Square x 1-1/2" Deep

4-11/16" x 4-11/16" x 1-1/2"

29.5 cu.in.Max 14 × 14AWG

4-11/16" Square x 2-1/8" Deep

4-11/16" x 4-11/16" x 2-1/8"

42 cu.in.Max 21 × 14AWG

Octagon Box 1-1/2" Deep

4" Octagon x 1-1/2"

15.5 cu.in.Max 7 × 14AWG

4" Octagon Box 1-1/2" Deep

4" Octagon x 1-1/2"

15.5 cu.in.Max 7 × 14AWG

Octagon Box 2-1/8" Deep

4" Octagon x 2-1/8"

21.5 cu.in.Max 10 × 14AWG

Single Gang Device Box 2-3/4" Deep

3" x 2" x 2-3/4"

14 cu.in.Max 7 × 14AWG

Single Gang Device Box 18 cu.in.

3" x 2" x 3-1/2"

18 cu.in.Max 9 × 14AWG

Single Gang Device Box 3-1/2" Deep

3" x 2" x 3-1/2"

18 cu.in.Max 9 × 14AWG

2-Gang Device Box 2-3/4" Deep

4" x 3" x 2-3/4"

28 cu.in.Max 14 × 14AWG

2-Gang Device Box 3-1/2" Deep

4" x 3" x 3-1/2"

36 cu.in.Max 18 × 14AWG

3-Gang Device Box 2-3/4" Deep

5-5/8" x 3" x 2-3/4"

42 cu.in.Max 21 × 14AWG

4-Gang Device Box 2-1/8" Deep

7-1/4" x 3" x 2-1/8"

50 cu.in.Max 25 × 14AWG

Handy Box 1-1/2" Deep

4" x 2-1/8" x 1-1/2"

10.3 cu.in.Max 5 × 14AWG

Handy Box 1-7/8" Deep

4" x 2-1/8" x 1-7/8"

13 cu.in.Max 6 × 14AWG

Handy Box 2-1/8" Deep

4" x 2-1/8" x 2-1/8"

14.5 cu.in.Max 7 × 14AWG

Masonry Box 3-1/2" Deep

3-3/4" x 4" x 3-1/2"

21 cu.in.Max 10 × 14AWG

FS Box Single Gang

4" x 2" x 2"

13.5 cu.in.Max 6 × 14AWG

FD Box Single Gang

4" x 2" x 2-5/8"

18 cu.in.Max 9 × 14AWG

FS Box 2-Gang

4" x 4" x 2"

24 cu.in.Max 12 × 14AWG

Round Pan Box 1/2" Deep

4" Round x 1/2"

4 cu.in.Max 2 × 14AWG

PVC Electrical Boxes

PVC Single Gang Box 18 cu.in.

3" x 2-1/4" x 3-3/4"

18 cu.in.Max 9 × 14AWG

PVC Single Gang Box 20 cu.in.

3" x 2-1/4" x 4"

20 cu.in.Max 10 × 14AWG

PVC Single Gang Box 22 cu.in.

3" x 2-1/4" x 4-1/4"

22.5 cu.in.Max 11 × 14AWG

PVC 2-Gang Box 32 cu.in.

4" x 3-1/4" x 3"

32 cu.in.Max 16 × 14AWG

PVC 3-Gang Box 44 cu.in.

5-3/4" x 3-1/4" x 3"

44 cu.in.Max 22 × 14AWG

PVC 4-Gang Box 60 cu.in.

7-1/2" x 3-1/4" x 3"

60 cu.in.Max 30 × 14AWG

PVC Round Ceiling Box 20 cu.in.

4" Round x 2-1/4"

20 cu.in.Max 10 × 14AWG

Old Work Box 1-Gang 14 cu.in.

3" x 2" x 2-3/4"

14 cu.in.Max 7 × 14AWG

Old Work Box 1-Gang 18 cu.in.

3" x 2" x 3-1/2"

18 cu.in.Max 9 × 14AWG

Old Work Box 2-Gang 32 cu.in.

4" x 3" x 3"

32 cu.in.Max 16 × 14AWG

Understanding Electrical Box Sizes

Selecting the right electrical box size is crucial for NEC compliance and safe installations. Each box type has a specific volume that determines how many conductors and devices it can accommodate per NEC 314.16.

Metal vs PVC Boxes

Metal boxes are required when using metal conduit or where physical protection is needed. They provide better grounding and are more durable.

PVC boxes are used with non-metallic cable (Romex) in residential construction. They're lightweight, corrosion-resistant, and don't require separate grounding.

How to Choose the Right Box

  1. Count all conductors that will enter the box
  2. Add devices (switches, receptacles)
  3. Calculate total fill volume needed
  4. Select a box with adequate volume
  5. Verify with our box fill calculator