In construction and woodworking, a 2x4 is never actually 2 inches by 4 inches. Our Lumber Size Converter bridges the gap between 'nominal' names and 'actual' dressed dimensions. We provide the precise measurements for standard S4S (Surfaced 4 Sides) lumber, ensuring your architectural drawings and woodworking joints are accurate to the fraction of an inch.
Lumber Size Converter
Find the actual dimensions of standard finished lumber based on its nominal name.
Nominal to Actual Chart
In the US and Canada, "Nominal" size refers to the wood's dimensions before it is dried and planed.
Why the Difference?
Lumber is cut at the "nominal" size while wet. As it dries, it shrinks. Finally, it is planed (surfaced) to create smooth, consistent surfaces, further reducing its size.
Measurement Tip
When building structures, always use the **actual** dimensions for your calculations to ensure precise fitting and structural integrity.
About Nominal to Actual Lumber Sizes
Select Nominal
Choose the common name like 2x4 or 2x6.
See Actual
The tool shows the exact dressed dimensions after drying and planing.
Review Results
Verify the output looks correct before using or downloading it.
Save Your Output
Click the download or copy button to export your results to your device or clipboard.
Key Features
Dressed Dimension Mapping
Correctly identifies the actual width and thickness of lumber after drying and planing.
Board Foot Calculator
Estimate volume and material costs based on nominal dimensions and length.
Softwood & Hardwood Guide
Accounts for different sizing standards between common construction pine and premium hardwoods.
Frequently Asked Questions
2x4 is the 'nominal' size before the wood is planed and dried. Dressing the lumber reduces its size.
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