2x3 actual size
1½ × 2½ inches
3.8 × 6.3 cm · 38 × 64 mm · sold as a 2x3
Nominal against actual
| Nominal | Actual | Difference | |
|---|---|---|---|
| Thickness | 2 in | 1½ in (38 mm) | −½ in |
| Width | 3 in | 2½ in (64 mm) | −½ in |
| Cross-section | 6 in² | 3.75 in² | −38% |
What a 2x3 is for
Non-load-bearing partition walls, where the thinner wall saves floor area. Common in older houses and in interior partitions that carry nothing.
The name is the rough-sawn size before drying and planing. Why every board is smaller than its name →
What this costs you in practice
The error compounds wherever boards sit side by side. Three 2x3s are 7½ inches across, not 9; eight of them are 20 inches rather than 24, which is 4 inches short over a run you might have measured on paper. That is why framing is dimensioned centre to centre and not edge to edge: 16 inches on centre is a real 16 inches whatever the boards themselves measure, so a sheet of plywood still lands on a stud.
Other 2-inch nominal boards
| Nominal | Actual | In mm |
|---|---|---|
| 2x2 | 1½ × 1½ in | 38 × 38 mm |
| 2x4 | 1½ × 3½ in | 38 × 89 mm |
| 2x6 | 1½ × 5½ in | 38 × 140 mm |
| 2x8 | 1½ × 7¼ in | 38 × 184 mm |
| 2x10 | 1½ × 9¼ in | 38 × 235 mm |
| 2x12 | 1½ × 11¼ in | 38 × 286 mm |
Frequently asked questions
What is the actual size of a 2x3?
1½ × 2½ inches — 3.8 × 6.3 cm, or 38 × 64 mm.
Why is a 2x3 not 2 by 3 inches?
Because it was, once. The board is sawn at roughly its nominal size while green, then dried and planed smooth on all four faces, and both processes take material off. The name records the rough-sawn size and the label never caught up. This is standardised, not accidental — every mill in North America surfaces to the same finished dimensions.
How much smaller is a 2x3 than its name?
½ inch off the thickness and ½ off the width, which is 38% less cross-section than the name implies. That matters for spans and for anything where you are counting boards to fill a width.
What lengths does a 2x3 come in?
Typically 6, 8, 10, 12, 14, 16, 20 feet. Unlike the cross-section, length is not reduced — an 8-foot board is 8 feet, or a little over, because it is cut to length after planing.