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 sizes so many common North American lumber sizes.
Softwood lumber comes in a number of standard lengths as listed in the table below.
Length in Feet
Length in Inches
Length in Meters
Hardwood Lumber Dimensions
Hardwood lumber is sized based on how many sides are surfaced. Surfaced refers to a finishing process that smooths the lumber to remove all saw marks.
In North America, hardwood lumber is usually specified using the quarter system, where a board is identified by its thickness in quarters of an inch. For instance, hardwood trim that ends up being just over 1" thick (surfaced on 2 sides) is called a five-quarter (5/4) board.
Hardwood board widths vary. In most cases, hardwood boards come in random widths to be ripped to size by the woodworker. However, in some cases, like the big-box hardware stores, the boards come in dimensional widths similar to softwood widths. It is advisable to check with your contractor or lumber supplier before finalizing design details so you aren't surprised by what you receive.
ANSI/AITC A190.1-1992 allows for any width and depth of glue laminated timber. Standard widths are specified in the above publication, but can be customized as needed. A wide range of depths are available, far to many to list here, so please contact your local manufacturer for more information on their offerings - in general depths start at 6" and go up to 30" and beyond. Of course, lengths are customized for each job.
Actual Finished Width
3 1/8" or 3 1/2"
5 1/8" or 5 1/2"
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