Lumber Dimensions:
Nominal vs Actual
Dimensional lumber is cut to a specific length, width, and depth. However, there is a difference between the nominal size (what the lumber is referred to) and the actual size. The tables below provide both the nominal and actual lumber dimensions for many common North American lumber sizes.
Table 1 – Softwood Lumber Dimensions
| NOMINAL SIZE (INCHES) | ACTUAL SIZE (INCHES) | ACTUAL SIZE (MM) |
|---|---|---|
1 x 2 | 3/4 x 1 1/2 | 19 x 38 |
1 x 3 | 3/4 x 2 1/2 | 19 x 64 |
1 x 4 | 3/4 x 3 1/2 | 19 x 89 |
1 x 6 | 3/4 x 5 1/2 | 19 x 140 |
1 x 8 | 3/4 x 7 1/4 | 19 x 184 |
1 x 10 | 3/4 x 9 1/4 | 19 x 235 |
1 x 12 | 3/4 x 11 1/4 | 19 x 286 |
2 x 2 | 1 1/2 x 1 1/2 | 38 x 38 |
2 x 3 | 1 1/2 x 2 1/2 | 38 x 64 |
2 x 4 | 1 1/2 x 3 1/2 | 38 x 89 |
2 x 6 | 1 1/2 x 5 1/2 | 38 x 140 |
2 x 8 | 1 1/2 x 7 1/4 | 38 x 184 |
2 x 10 | 1 1/2 x 9 1/4 | 38 x 235 |
2 x 12 | 1 1/2 x 11 1/4 | 38 x 286 |
4 x 4 | 3 1/2 x 3 1/2 | 89 x 89 |
4 x 6 | 3 1/2 x 5 1/2 | 89 x 140 |
4 x 8 | 3 1/2 x 7 1/4 | 89 x 184 |
4 x 10 | 3 1/2 x 9 1/4 | 89 x 235 |
4 x 12 | 3 1/2 x 11 1/4 | 89 x 286 |
6 x 6 | 5 1/2 x 5 1/2 | 140 x 140 |
6 x 8 | 5 1/2 x 7 1/2 | 140 x 191 |
6 x 10 | 5 1/2 x 9 1/2 | 140 x 241 |
6 x 12 | 5 1/2 x 11 1/2 | 140 x 292 |
8 x 8 | 7 1/2 x 7 1/2 | 191 x 191 |
8 x 10 | 7 1/2 x 9 1/2 | 191 x 241 |
8 x 12 | 7 1/2 x 11 1/2 | 191 x 292 |
Table 2 – Softwood Lumber Lengths
| LENGTH IN FEET | LENGTH IN INCHES | LENGTH IN METERS |
|---|---|---|
6 feet | 72 inches | 1.829 meters |
8 feet | 96 inches | 2.438 meters |
10 feet | 120 inches | 3.048 meters |
12 feet | 144 inches | 3.658 meters |
14 feet | 168 inches | 4.267 meters |
16 feet | 192 inches | 4.877 meters |
18 feet | 216 inches | 5.486 meters |
20 feet | 240 inches | 6.096 meters |
22 feet | 264 inches | 6.706 meters |
24 feet | 288 inches | 7.315 meters |
Table 3 – Hardwood Lumber Dimensions
| NOMINAL SIZE | ROUGH SIZE | ACTUAL SIZE : SURFACED 1 SIDE | ACTUAL SIZE : SURFACED 2 SIDES |
|---|---|---|---|
– | 1/2 inch | 3/8 inch (9.5 mm) | 5/16 inch (7.9 mm) |
_ | 5/8 inch | 1/2 inch (13 mm) | 7/16 inch (11 mm) |
_ | 3/4 inch | 5/8 inch (16 mm) | 9/16 inch (14 mm) |
4/4 inch | 1 inch | 7/8 inch (22 mm) | 13/16 inch (21 mm) |
5/4 inch | 1 1/4 inch | 1 1/8 inch (29 mm) | 1 1/16 inch (27 mm) |
6/4 inch | 1 1/2 inch | 1 3/8 inch (35 mm) | 1 5/16 inch (33 mm) |
8/4 inch | 2 inches | 1 13/16 inch (46 mm) | 1 3/4 inch (44 mm) |
12/4 inch | 3 inches | 2 13/16 inch (71 mm) | 2 3/4 inch (70 mm) |
16/4 inch | 4 inches | 3 13/16 inch (97 mm) | 3 3/4 inch (95 mm) |
Table – 4 Glue Laminated Lumber Dimensions
| NOMINAL WIDTH | ACTUAL FINISHED WIDTH |
|---|---|
3" | 2 1/2" |
4" | 3 1/8" or 3 1/2" |
6" | 5 1/8" or 5 1/2" |
8" | 6 3/4" |
10" | 8 3/4" |
12" | 10 3/4" |
14" | 12 1/4" |
16" | 14 1/4" |