Nominal vs. Actual Lumber & Plywood Dimensions Chart (Inches & mm)
Softwood dimensional lumber is sold by its rough-sawn nominal size, not its dried, planed actual size: a 1x3 actually measures 3/4" × 2-1/2" (19mm × 63.5mm), a 1x4 measures 3/4" × 3-1/2" (19mm × 88.9mm), and '3/4" plywood' typically measures 23/32" (18.2mm) or 18mm (Baltic Birch).
Master Reference Lookup Table
Filter by name or click column headers to sort specifications.
| Action | ||||
|---|---|---|---|---|
| 1x2 Lumber | 0.75" × 1.5" | 19.05mm × 38.1mm | Narrow battens, face frames, light framing | Cabinet Hub → |
| 1x3 Lumber | 0.75" × 2.5" | 19.05mm × 63.5mm | Standard modern board & batten vertical stiles | Cabinet Hub → |
| 1x4 Lumber | 0.75" × 3.5" | 19.05mm × 88.9mm | Traditional wide board & batten, top horizontal rails, baseboard caps | Cabinet Hub → |
| 1x6 Lumber | 0.75" × 5.5" | 19.05mm × 139.7mm | Tall baseboard backing, accent wall headers | Cabinet Hub → |
| MDF 1/2" Board (Custom Ripped) | 0.5" × 2.5" | 12.7mm × 63.5mm | Budget paint-grade board and batten wall stiles with no grain texture | Cabinet Hub → |
Core Mathematical & Engineering Breakdown
Datasheet equations, derivations, and step-by-step worked shop math.
How Nominal vs. Actual Sizing Wrecks Board & Batten and Drawer Box Math
Calculating wall or cabinetry layouts using nominal callouts leads to severe compounding error. If a contractor plans a 10-batten accent wall assuming 1x4 boards are 4.0" wide, the calculation assumes 40.0" of wall coverage. Because actual 1x4 boards are 3.5" wide, the actual board coverage is only 35.0"—creating a massive 5.0" gap spacing layout error across the room.
Baltic Birch Metric Ply (12mm, 15mm, 18mm) vs. North American Veneer Core
European Baltic birch plywood is manufactured on a strict metric system: 1/2" nominal is 12.0mm (0.472"), 5/8" is 15.0mm (0.591"), and 3/4" is 18.0mm (0.709"). In contrast, domestic US softwood and hardwood plywood is manufactured to 15/32" (0.469") and 23/32" (0.718"). Routing a 3/4" (0.750") groove with a standard straight bit produces loose, sloppy joints with domestic plywood. Always use undersized plywood bits (e.g., 23/32" router bits).
Kerf Width Loss During Ripping & Planing
Standard 10" table saw blades feature a 1/8" (3.175mm) kerf, while thin-kerf blades cut 3/32" (2.38mm). Ripping four 6" wide strips from a 24" wide panel loses 1/2" of stock to sawdust (4 cuts × 1/8"), leaving the final strip undersized at only 5-1/2". Always add blade kerf allowance to cut-list planning.
Interactive Micro-Tool: Real-Time Calculation
Adjust sliders and inputs below to calculate custom dimensions instantly.
Cabinet Opening & Slide Hardware
Pre-loads exact manufacturer deduction (1.9375") and bottom recess.
Exact clear opening measured between cabinet face-frame or sidewalls.
Selects a 21" nominal runner length while preserving cabinet rear clearance.
Opening 24" minus 1.9375" hardware clearance
Saw cut between 2 sides
Clearance top & bottom
Workshop Saw Cut-List (Dadoed Bottom)
- 2x Drawer Sides:21" × 4 5/8"
- 2x Front / Back Sub:20 13/16" × 4 5/8"
- 1x Bottom Panel:21 5/16" × 20 1/4"
- Bottom Recess / Dado:1/2" recess; 6.35mm dado depth
Order Blum Tandem 563H / 563F (5/8" Material) Runners
Genuine full-extension runners with integrated soft-close dampers and locking device clips.
Failure Modes & Workshop Troubleshooting Matrix
Common fabrication failures, caliper inspection methods, and prevention rules.
| Failure Mode | Root Cause | Caliper / Scale Check | Shop Prevention |
|---|---|---|---|
| Plywood panel rattles loosely inside routed dado groove | Standard 3/4" (0.750") router bit used for 23/32" (0.718") or 18mm (0.709") plywood stock | Caliper measurement shows dado slot is 0.752" wide while plywood sheet is only 0.714" | Use dedicated undersized plywood router bits (23/32") or cut dados with adjustable dial dado stacks |
| Accent wall battens run off the right corner by several inches | Wall spacing calculated using nominal lumber widths (3.0" or 4.0") instead of actual (2.5" or 3.5") | Cumulative error across 8 battens totals 8 × 0.5" = 4.0" drift | Input actual dressed lumber caliper dimensions directly into MetriFab Batten Calculator |
| Cabinet face frame overhangs cabinet carcass | Assuming 1x2 face frame stiles measure 2.0" instead of 1.50" (38.1mm) | Outside carcass is 36.0" wide but face frame built to nominal math is 37.0" | Verify all face frame member cut sheets against actual dressed stock dimensions |
Frequently Asked Engineering Questions
High-intent technical fabrication inquiries verified against lab standards.
Q1What are the actual dimensions of a 1x4 and 2x4 board?
Q2Why is 3/4 inch plywood actually 23/32 inch thick?
Q3How does metric Baltic birch plywood compare to nominal US plywood?
Q4How do I calculate the total lumber thickness in a multi-layer face frame?
Related Programmatic Calculators in this Silo
Launch individual entity calculators pre-configured with exact manufacturer specifications: