2×8 Actual Size? – What Are The Actual Measurements And Why?

2×8 actual size

A 2×8 board is 1 1/2 x 7 1/4 inches (38 x 184 mm) dimensions in actuality. The board which is advertised and being sold by using nominal dimensions are a bit larger in size as compared to the actual size.

You might have seen the frame softwood boards or framing lumber that is being sold at any local hardware store or lumber yard that advertised those dimensions that do not match with the actual size of the frame board.

Dimensional lumber is being cut to a specific width, length, and depth. Although, there is a small difference between the actual size and the nominal size (to whom the framing lumber is being referred).

Actual Size of Dimensional Lumber

Most of the softwood lumber that has been sold at the lumber yard store is dimensional lumber. Dimensional lumber is basically lumber that has been milled and dried to standard dimensions and is mostly used for construction and framing.

Dimensional lumber is being sold by using those nominal dimensions of the board that are not in actual. These are the dimensions of the board prior to it’s been milled and dried. But in reality, the actual sizes of a board are a bit smaller than the actual ones.

For instance, a 2×8 board is referring to have 1 1/2 x 7 1/4 inches (38 x 184 mm) dimensions in actuality. The board which is advertised and being sold by using nominal dimensions are a bit larger in size as compared to the actual size.

You may use a simple thumb rule that is to ascertain the actual size of dimensional lumber.

  • If the nominal size is less than 1,” then the actual size of the board will be 1/4” inches less than the nominal size.
  • If the nominal size is equal to 8” or larger than this, then its actual size will be 3/4” inches smaller.
  • If the nominal size is more than 2″ and less than 8,” then the actual size of the board will be 1/2″ inches smaller as compared to the nominal size.

Why dimensional lumber is smaller as compared to nominal dimensions?

In history, the softwood logs were cut into 2 x 8, but they naturally shrink as boards dry, and after milling and planing, they end up on 1.5×7.25. These days, boards are deliberately cut into large in order to allow the shrinkage while the milling procedure and kiln drying.

As the amount of a board that shrinks may vary by moisture content, wood species, and with the individual tree, so the final size may also vary slightly. Modern sawmills mostly account for this, and dimensional lumber is generally quite consistent.

1x Board Sizes

1×6 and 1×4 boards lose 1/4 inch in its thickness and 1/2 inch in its width prior to leaving the mill that means a 1×4 board is actually 3 1/2 inches by 3/4 inches. The larger 1x boards (1×10, 1×8, etc.) lose 3/4 inches in their width. Which means a 1×10 is in actual 3/4 inches in its thickness by 9 1/4 inch.

2x Board Sizes

2×6 and 2×8 boards lost 1/2 inches in its thickness and 1/2 inches in its width just prior to leaving the mill. This means a 2×4 board is actually 3-1/2 inches by 1-1/2 inches. The larger 2x boards (2×10, 2×8, etc.) lost 3/4 inches of its width. This means a 2×8 actual size is 1 1/2 inches in its thickness by 7 1/4 inches.

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