Understanding Dimensional Lumber Sizes: Nominal vs. Actual Dimensions
When working on construction or woodworking projects, choosing the right lumber size is crucial. However, the dimensions listed for lumber can be misleading. Terms like “1x4” or “2x6” are nominal sizes, not the actual measurements of the board. Let’s break this down.
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1/18/20251 min read
What is Nominal Size?
The nominal size refers to the rough-cut dimension of the lumber before it is planed smooth. This is the size when the wood is first sawn and has not yet been milled or dried.
What is Actual Size?
The actual size is the final dimension of the lumber after the milling process. Planing and smoothing reduce the board’s thickness and width. For instance:
• A “1x4” board actually measures ¾ inch thick by 3½ inches wide.
• A “2x4” board is actually 1½ inches thick by 3½ inches wide.
Why Does This Happen?
The difference between nominal and actual dimensions is due to the manufacturing process. The wood is cut to its nominal size but loses material during drying and finishing.
Common Dimensional Lumber Sizes:
Here is a quick reference for 1-inch-thick boards:
• 1”x1” → ¾”x¾”
• 1”x2” → ¾”x1½”
• 1”x3” → ¾”x2½”
• 1”x4” → ¾”x3½”
• 1”x6” → ¾”x5½”
• 1”x8” → ¾”x7¼”
• 1”x10” → ¾”x9¼”
• 1”x12” → ¾”x11¼”
Why Understanding These Sizes Matters
Knowing the difference between nominal and actual sizes is vital for accurate planning and measurements. For example, if you’re building a table or framing a wall, relying solely on nominal dimensions can lead to incorrect cuts and misaligned joints.
Pro Tip
When purchasing lumber for a project:
• Always double-check the actual dimensions listed on the board.
• Account for these differences in your plans to avoid miscalculations.
Conclusion
Dimensional lumber sizes can be confusing, but understanding the difference between nominal and actual dimensions ensures your projects are precise and professional. Whether you’re a contractor or a DIY enthusiast, this knowledge is an essential tool for success.
For professional renovation and handyman services in Glendale, Burbank, Pasadena, and surrounding areas, contact ProHands Handyman:
• Phone: 818-401-7766
• Website: www.prohandshandyman.com
• Email: info@prohandshandyman.com
