Nominal Size – Refers to the size of a piece of lumber before it is dressed
and seasoned. It is used to designate a particular size piece of lumber,
such as 2×4, 2×6, etc.

Actual Size – Refers to minimum acceptable size after it has been
dressed and seasoned. A nominal 2×4 can have a minimum actual size of
1.5 in. x 3.5 in. When referring to a specific piece of lumber, the nominal
size is used.

Size Chart For Framing Lumber

Nominal Size

Actual Size

2 x 2

1 1/2 x 1 1/2

2 x 3

1 1/2 x 2 1/2

2 x 4
1 1/2 x 3 1/2

2 x 6
1 1/2 x 5 1/2

2 x 8
1 1/2 x 7 1/4

2 x 10
1 1/2 x 9 1/4

2 x 12
1 1/2 x 11 1/4

4 x 4
3 1/2 x 3 1/2

4 x 6
3 1/2 x 5 1/2

4 x 10
3 1/2 x 9 1/4

6 x 6
5 1/2 x 5 1/2

Boards

Nominal Size
Actual Size

1 x 2
3/4 x 1 1/2

1 x 3
3/4 x 2 1/2

1 x 4
3/4 x 3 1/2

1 x 5
3/4 x 4 1/2

1 x 6
3/4
x 5 1/2

1 x 8
3/4 x 7 1/4

1 x 10
3/4 x 9 1/4

1 x 12
3/4 x 11 1/4

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