Compare nominal lumber and common sheet-goods sizes against actual inch and millimetre dimensions for board and panel planning.
Last updated
Home & DIY
Cross-reference common dimensional lumber sizes and sheet goods in inches and millimetres. Switch between nominal and actual lookup, then compare the match against the full reference tables.
Reference type
Lookup mode
What this tool covers
Dimensional lumber uses common nominal boards and posts. Sheet goods cover standard panel sizes plus a short list of common thickness grades with their actual inch and millimetre values.
Result
Dimensional lumber
A standard nominal board size with actual dressed dimensions.
Reference note
Actual lumber sizes are dressed sizes. Nominal dimensions are the market names, not the finished measurements.
Dimensional lumber reference
The active table is highlighted below, and the other reference table stays visible for quick comparison.
Dimensional lumber
17 sizes
| Nominal | Actual in | Actual mm |
|---|---|---|
| 1×2 | 0.75 in × 1.5 in | 19 mm × 38 mm |
| 1×3 | 0.75 in × 2.5 in | 19 mm × 64 mm |
| 1×4 | 0.75 in × 3.5 in | 19 mm × 89 mm |
| 1×6 | 0.75 in × 5.5 in | 19 mm × 140 mm |
| 1×8 | 0.75 in × 7.25 in | 19 mm × 184 mm |
| 1×10 | 0.75 in × 9.25 in | 19 mm × 235 mm |
| 1×12 | 0.75 in × 11.25 in | 19 mm × 286 mm |
| 2×2 | 1.5 in × 1.5 in | 38 mm × 38 mm |
| 2×3 | 1.5 in × 2.5 in | 38 mm × 64 mm |
| 2×4 | 1.5 in × 3.5 in | 38 mm × 89 mm |
| 2×6 | 1.5 in × 5.5 in | 38 mm × 140 mm |
| 2×8 | 1.5 in × 7.25 in | 38 mm × 184 mm |
| 2×10 | 1.5 in × 9.25 in | 38 mm × 235 mm |
| 2×12 | 1.5 in × 11.25 in | 38 mm × 286 mm |
| 4×4 | 3.5 in × 3.5 in | 89 mm × 89 mm |
| 4×6 | 3.5 in × 5.5 in | 89 mm × 140 mm |
| 6×6 | 5.5 in × 5.5 in | 140 mm × 140 mm |
Sheet goods
18 entries
| Nominal | Panel size in | Panel size mm | Thickness |
|---|---|---|---|
| 4×8×1/4 | 48 in × 96 in | 1220 mm × 2440 mm | 0.234 in / 6 mm |
| 4×8×3/8 | 48 in × 96 in | 1220 mm × 2440 mm | 0.344 in / 9 mm |
| 4×8×1/2 | 48 in × 96 in | 1220 mm × 2440 mm | 0.469 in / 12 mm |
| 4×8×5/8 | 48 in × 96 in | 1220 mm × 2440 mm | 0.594 in / 15 mm |
| 4×8×3/4 | 48 in × 96 in | 1220 mm × 2440 mm | 0.703 in / 18 mm |
| 4×8×1 | 48 in × 96 in | 1220 mm × 2440 mm | 0.938 in / 24 mm |
| 4×10×1/4 | 48 in × 120 in | 1220 mm × 3050 mm | 0.234 in / 6 mm |
| 4×10×3/8 | 48 in × 120 in | 1220 mm × 3050 mm | 0.344 in / 9 mm |
| 4×10×1/2 | 48 in × 120 in | 1220 mm × 3050 mm | 0.469 in / 12 mm |
| 4×10×5/8 | 48 in × 120 in | 1220 mm × 3050 mm | 0.594 in / 15 mm |
| 4×10×3/4 | 48 in × 120 in | 1220 mm × 3050 mm | 0.703 in / 18 mm |
| 4×10×1 | 48 in × 120 in | 1220 mm × 3050 mm | 0.938 in / 24 mm |
| 5×5×1/4 | 60 in × 60 in | 1525 mm × 1525 mm | 0.234 in / 6 mm |
| 5×5×3/8 | 60 in × 60 in | 1525 mm × 1525 mm | 0.344 in / 9 mm |
| 5×5×1/2 | 60 in × 60 in | 1525 mm × 1525 mm | 0.469 in / 12 mm |
| 5×5×5/8 | 60 in × 60 in | 1525 mm × 1525 mm | 0.594 in / 15 mm |
| 5×5×3/4 | 60 in × 60 in | 1525 mm × 1525 mm | 0.703 in / 18 mm |
| 5×5×1 | 60 in × 60 in | 1525 mm × 1525 mm | 0.938 in / 24 mm |
Board & Panel Reference
A timber and sheet converter helps when site notes, supplier descriptions, and measured stock all describe the same material differently. Lumber is often bought by nominal size even though the dressed board is smaller in reality, while sheet goods mix panel format and nominal thickness with actual manufactured dimensions.
Nominal lumber sizes come from rough-sawn naming tradition, but planing and drying reduce the finished board dimensions. That is why a nominal 2×4 does not measure a full 2 inches by 4 inches once it is dressed for sale.
A lookup table is useful because the same mismatch repeats across common board sizes. It lets you translate supplier terminology into the dimensions that actually matter for framing, cabinetry, and fit checks.
Sheet goods usually combine panel format and nominal thickness. A panel might be sold as 4×8×3/4 even though the actual thickness is closer to about 18 mm or 0.703 inches rather than a true 0.75 inches.
That distinction matters whenever a groove, dado, frame opening, or hardware specification depends on actual panel thickness instead of the nominal trade label.
1 in = 25.4 mm
Core bridge between imperial and metric board and panel measurements.
actual size < nominal size
Common timber rule of thumb because dressing and manufacturing reduce the finished dimensions.
A plain unit converter can translate inches to millimetres, but it cannot tell you whether a measurement corresponds to a standard stocked size. This tool adds that reference layer by matching the input against common lumber sizes and common sheet formats with realistic tolerances.
That makes it useful for framing checks, panel cut planning, joinery, trim work, and material specification reviews where trade names and real dimensions both need to stay visible.
Frequently asked questions
Because the nominal name reflects a rough-sawn sizing convention, while the finished board has been dried and planed to smaller dressed dimensions before sale. The actual size is what matters for fit and layout.
Because sheet goods are commonly sold by nominal thickness, not exact finished thickness. Manufacturing tolerances and industry conventions mean the real panel is often slightly thinner than the trade label suggests.
Yes. The lookup supports both inch and millimetre inputs, then checks them against common nominal lumber sizes or standard panel formats within a practical tolerance.
No. It is a fast planning and translation reference. Final purchasing and joinery decisions should still confirm the exact stock dimensions, grade, and manufacturing tolerance from the supplier or product sheet.
Also in Construction & DIY
Related
These related calculators come from the same leaf category, nearby sibling categories, or the same top-level topic.
Cross-reference nominal pipe sizes between DN, NPS, and actual outer diameter in millimetres or inches for plumbing and HVAC planning.
Convert lumber volume between board feet, MBF, cubic feet, cubic inches, cubic metres, and the standard 1×12 linear-foot shortcut.
Estimate paint quantity from room dimensions or wall area, then adjust for openings, coats, waste allowance, and litres-to-gallon coverage.
Convert fuel economy between MPG (US), MPG (UK), km/L, and L/100 km, with all equivalents shown at once plus range examples for common tank sizes.
