The name is a lie: as anyone who has ever designed and built something using 2x4s can tell you, a 2x4 is in fact 1.5x3.5 inches. Maybe you can doublethink yourself into using 2x4 2x4s, but you might find that your bolts are awfully short.
Nominal Size Actual Size
1 X 3 .75 X 2.5
1 X 4 .75 X 3.5
1 X 6 .75 X 5.5
1 X 8 .75 X 7.25
1 X 10 .75 X 9.25
1 X 12 .75 X 11.25
2 X 3 1.5 X 2.5
2 X 4 1.5 X 3.5
2 X 6 1.5 X 5.5
2 X 8 1.5 X 7.25
2 X 10 1.5 X 9.25
2 X 12 1.5 X 11.25
2 X 14 1.5 X 13.25
3 X 3 2.5 X 2.5
3 X 4 2.5 X 3.5
3 X 6 2.5 X 5.5
3 X 8 2.5 X 7.25
3 X 10 2.5 X 9.25
3 X 12 2.5 X 11.25
3 X 14 2.5 X 13.25
3 X 16 2.5 X 15.25
4 X 4 3.5 X 3.5
4 X 6 3.5 X 5.5
4 X 8 3.5 X 7.25
4 X 10 3.5 X 9.25
4 X 12 3.5 X 11.25
4 X 14 3.5 X 13.25
4 X 16 3.5 X 15.25
6 X 6 5.5 X 5.5
6 X 8 5.5 X 7.5
6 X 10 5.5 X 9.5
6 X 12 5.5 X 11.5
6 X 14 5.5 X 13.5
6 X 16 5.5 X 15.5
6 X 18 5.5 X 17.5
8 X 8 7.5 X 7.5
8 X 10 7.5 X 9.5
8 X 12 7.5 X 11.5
8 X 14 7.5 X 13.5
8 X 16 7.5 X 15.5
8 X 18 7.5 X 17.5
10 X 10 9.5 X 8.5
10 X 12 9.5 X 11.5
10 X 14 9.5 X 13.5
10 X 16 9.5 X 15.5
10 X 18 9.5 X 17.5
12 X 12 11.5 X 11.5
12 X 14 11.5 X 13.5
12 X 16 11.5 X 15.5
Source: http://www.engineersedge.com/commercial_lumber_sizes.htm
Confirmed using
hardware store and
yardstick, and to some extent, personal experience.
cbustapeck says re
A 2x4 is 2x4: Hey, are you sure a 10 x 10 is actually 9.5 x 8.5? Shouldn't it be 9.5 x 9.5
Good point. Time to make a call.
Beep Boop Beep Bap Boop Beep Beep.
Ring. Ring. Ring.
Chipper hardware store employee: Hi! Well come to Ace Hardware, how may I direct your call?
Me: Hi, I have a question about the size of lumber.
Chipper: OK, hold on.
Silence........for about 3 minutes.
Me: (hangs up) (redials)
Chipper hardware store employee: Hi! Well come to Ace Hardware, how may I direct your call?
Me: Hi, I have a question about the size of lumber.
Chipper: Uh...um...hold on.
Silence........for about 1 minute.
Ring. Ring.
Chipper: Wha....
Me: Hello?
Chipper: Oh. Let me try again.
Silence........for about 1 minute.
Ring. Ring.
Lumberjack Jack: YeeeeeeEEEllo! Lumber department.
Me: Hi, I have a question about the size of lumber.
Jack: YEAH! Sure, what is it?
Me: Exactly how big is a 10 x 10?
Brief silence.
Jack: You mean a 1 x 10 x 10 or a 2 x 10 x 10?
Me: No, no, a 10 x 10. As opposed to a 2 x 4. 10 x 10 x 16, or whatever.
Jack: What? I don't sell that shit. That's like a tree.
Me: Yeah, it's a big project.
Jack: I never heard of something like that.
Brief silence.
Jack: That's like a TREE, man.
Me: So you have no clue.
Jack: Wait, you mean like a 1 x 10, or what?
Me: Thanks. (hangs up)
So, cbustapeck, the answer to your question is nobody knows and it doesn't really matter anyway.
Tune in next week for: a call to the Department of the Interior.