Common surfaced board examples
These common US board dimensions are listed in Kreg’s K4 reference. Measure your own stock: rough lumber, species, surfacing, moisture and supplier specifications can produce different dimensions. The chart is a starting reference, not a tolerance specification.
| Nominal label | Actual thickness (in) | Actual width (in) |
|---|---|---|
| 1×2 | 3/4 | 1 1/2 |
| 1×3 | 3/4 | 2 1/2 |
| 1×4 | 3/4 | 3 1/2 |
| 1×6 | 3/4 | 5 1/2 |
| 2×4 | 1 1/2 | 3 1/2 |
| 2×6 | 1 1/2 | 5 1/2 |
| 2×8 | 1 1/2 | 7 1/4 |
| 4×4 | 3 1/2 | 3 1/2 |
Choose the input for the job
For a physical volume or weight estimate, use actual measured dimensions. For pocket-hole setup, use measured stock thickness and the jig’s instructions. For a lumber purchasing estimate, ask which dimensions the supplier uses for the tally. Those are different questions, and one table cannot decide all three.
An 8 ft board entered as 2 × 4 in contains 5.3333 board feet by geometric calculation. Entering 1.5 × 3.5 in instead gives 3.5 board feet. The formula has not changed; the dimensions describe different volumes.
Thickness matters for sheet goods too
Plywood and other sheet products are sold with nominal thicknesses that may not equal your measurement. A coverage calculation uses sheet length and width, but joinery, grooves and pocket-hole settings can depend on actual thickness. Check the product specification and measure before setting a cut.
Do not automatically apply a dimensional-lumber conversion to hardwood sold rough, surfaced to a stated thickness, or sold by another convention. The supplier’s product description is the appropriate starting point.
Use the right tool
- Board-foot calculator: enter the dimensions appropriate to volume or a confirmed tally.
- Wood weight calculator: use actual solid dimensions and a matching density.
- Pocket-hole reference: use the published model-specific setup.
- Plywood calculator: enter the actual usable sheet size for the grid.
Reference
Kreg K4 owner’s manual, common board sizes. Reference checked November 7, 2026. See our calculation methodology for how input dimensions are handled.