Sizing Guide
Understand lumber dimensions, board foot calculations, and how reclaimed wood sizing compares to modern nominal standards.
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Nominal vs. Actual Dimensions
When you buy a "2x4" from a modern lumber yard, you are not getting a board that measures 2 inches by 4 inches. The "nominal" size refers to the rough-cut dimension before drying and planing. After kiln drying and surfacing, the board shrinks to its "actual" dimension — typically 1/2" to 3/4" smaller in each direction.
Modern Lumber (Nominal)
Modern dimensional lumber is rough-sawn to its nominal size, then kiln dried and planed smooth. This process removes material, resulting in smaller actual dimensions. A nominal 2x4 starts as a true 2" x 4" board, but after drying and surfacing, it becomes 1-1/2" x 3-1/2". This has been the industry standard since 1964 when the American Lumber Standard Committee adopted the current sizing rules.
Reclaimed Lumber (True Dimension)
Reclaimed lumber from pre-1964 structures is often "true dimension" — a reclaimed 2x4 may actually measure a full 2" x 4" or very close to it. This is because older sawmills did not plane the wood as aggressively, and historical lumber standards allowed larger finished sizes. This extra material means greater structural capacity and more wood to work with for your project.
Quick Reference: Nominal to Actual
| Nominal Size | Actual (Dry) | Metric Equivalent |
|---|---|---|
| 1 x 2 | 3/4" x 1-1/2" | 19 x 38 mm |
| 1 x 3 | 3/4" x 2-1/2" | 19 x 64 mm |
| 1 x 4 | 3/4" x 3-1/2" | 19 x 89 mm |
| 1 x 6 | 3/4" x 5-1/2" | 19 x 140 mm |
| 1 x 8 | 3/4" x 7-1/4" | 19 x 184 mm |
| 1 x 10 | 3/4" x 9-1/4" | 19 x 235 mm |
| 1 x 12 | 3/4" x 11-1/4" | 19 x 286 mm |
| 2 x 2 | 1-1/2" x 1-1/2" | 38 x 38 mm |
| 2 x 4 | 1-1/2" x 3-1/2" | 38 x 89 mm |
| 2 x 6 | 1-1/2" x 5-1/2" | 38 x 140 mm |
| 2 x 8 | 1-1/2" x 7-1/4" | 38 x 184 mm |
| 2 x 10 | 1-1/2" x 9-1/4" | 38 x 235 mm |
| 2 x 12 | 1-1/2" x 11-1/4" | 38 x 286 mm |
| 4 x 4 | 3-1/2" x 3-1/2" | 89 x 89 mm |
| 6 x 6 | 5-1/2" x 5-1/2" | 140 x 140 mm |
Board Foot Calculation
A board foot (BF) is the standard unit of measurement for hardwood lumber. One board foot equals a piece of wood 12 inches long, 12 inches wide, and 1 inch thick — or 144 cubic inches of wood.
The Formula
Board Feet = (Thickness" x Width" x Length") / 144
When using this formula, always use the nominal thickness and width (in inches), and the actual length (in inches). If your length is in feet, use this simplified version:
Board Feet = (Thickness" x Width" x Length') / 12
Example Calculations
1x6 board, 8 feet long:
(1 x 6 x 8) / 12 = 4 board feet
2x10 board, 12 feet long:
(2 x 10 x 12) / 12 = 20 board feet
8/4 (2") hardwood, 7" wide, 10 feet long:
(2 x 7 x 10) / 12 = 11.67 board feet
6x6 timber, 16 feet long:
(6 x 6 x 16) / 12 = 48 board feet
Hardwood Thickness Standards
Hardwood lumber uses a "quarter" system to describe thickness. The number represents how many quarter-inches thick the rough board is before surfacing.
| Quarter Designation | Rough Thickness | Surfaced (S2S) |
|---|---|---|
| 4/4 | 1" | 13/16" |
| 5/4 | 1-1/4" | 1-1/16" |
| 6/4 | 1-1/2" | 1-5/16" |
| 8/4 | 2" | 1-13/16" |
| 10/4 | 2-1/2" | 2-5/16" |
| 12/4 | 3" | 2-13/16" |
| 16/4 | 4" | 3-13/16" |
Detailed Sizing Guides
Explore our in-depth reference pages for specific lumber categories. Each guide includes comprehensive tables, weight data, and notes specific to reclaimed wood.
Measuring Reclaimed Lumber
Reclaimed wood does not come off a production line. Each board carries the history of its previous life, which means irregular dimensions, slight warping, and surface variations are the norm rather than the exception. Accurate measuring is essential to a successful project.
Measure in Multiple Spots
Unlike modern lumber that holds consistent dimensions along its full length, a reclaimed board may be 1/8" wider at one end than the other. Always take width and thickness measurements at both ends and at the midpoint. Record the smallest measurement as your "working dimension" for joinery and layout purposes.
For boards longer than 8 feet, add a fourth measurement point at the quarter-length mark. This extra step takes seconds but prevents costly fitment issues during assembly.
Account for Surface Irregularities
Original saw marks, weathering, and embedded debris can create high and low spots on the face of a reclaimed board. Before measuring thickness, use a straight edge laid across the face to identify any crown, cup, or twist. Measure from the flat reference surface, not from a high spot caused by a raised grain line or old tool mark.
If you plan to surface the board smooth, subtract 1/16" to 1/8" per face from your measured thickness to estimate the finished dimension after planing.
Check for Taper and Bow
Many reclaimed boards — particularly those salvaged from barns and agricultural buildings — were originally rough-sawn with a natural taper. The butt end of the log produced a wider board than the tip end. Lay the board on a flat surface and measure the gap beneath it at the center to determine how much bow is present.
A bow of less than 1/4" over 8 feet is generally workable for most projects. Bows greater than 1/2" over 8 feet may require ripping the board into narrower strips or using it in shorter lengths.
Use the Right Tools
A standard tape measure works for length, but for width and thickness, use a dial or digital caliper accurate to 1/64". This level of precision matters when you are fitting reclaimed boards into a tongue-and-groove pattern or matching existing trim profiles.
A moisture meter is equally important. Pin-type meters give accurate readings for reclaimed wood. Insert the pins along the grain at the center of the board's cross section — surface readings can be misleadingly low because the outer layer dries faster than the core.
Tips for Measuring Nail-Hole Areas
Old nail holes, bolt holes, and mortise pockets are part of reclaimed wood's character. When measuring usable width, mark the location of each hole and determine whether it falls within a critical joinery zone. A nail hole in the middle of a shelf face is cosmetic; a nail hole at the location of a dado joint is structural.
For boards with extensive nail-hole patterns, measure the "clear zones" between holes. These clear spans are your true working dimensions for joinery. When in doubt, send us your measurements and photos — our team can help you determine the most efficient way to use the material.
Weight Estimation Guide
Knowing the weight of your lumber is critical for structural calculations, shipping estimates, and floor-load planning. Because reclaimed wood is typically denser than modern plantation-grown stock, the numbers below may actually be conservative for old-growth material. All weights assume kiln-dried lumber at approximately 12% moisture content.
| Species | Density (lbs/ft3) | Lbs per Board Foot | Common Reclaimed Source |
|---|---|---|---|
| White Oak | 47 | 3.92 | Barn frames, whiskey barrels |
| Red Oak | 44 | 3.67 | Factory flooring, pallets |
| Heart Pine | 42 | 3.50 | Southern mill buildings, churches |
| Douglas Fir | 34 | 2.83 | Warehouses, railroad trestles |
| American Chestnut | 30 | 2.50 | Pre-1920 barns, fencing |
| Eastern White Pine | 25 | 2.08 | New England barns, siding |
| Elm | 35 | 2.92 | Barn siding, wagon parts |
| Hard Maple | 44 | 3.67 | Gymnasium floors, bowling alleys |
How to Calculate Total Weight
Total Weight = Board Feet x Lbs per Board Foot
Example: 200 BF of White Oak
200 x 3.92 = 784 lbs
Example: 500 BF of Douglas Fir timbers
500 x 2.83 = 1,415 lbs
For shipping estimates, add approximately 10% to account for packaging, pallets, banding material, and moisture variation within the stack. When in doubt, we provide actual scale weights for all outbound shipments.
Coverage Calculator
When planning a flooring, paneling, or siding project, you need to know how many board feet or linear feet will cover a given area. The key variable is the "coverage width" — the exposed face of each board after accounting for tongue-and-groove overlap, shiplap rabbets, or spacing between boards.
Step 1: Calculate the Square Footage
Measure the length and width of the area in feet. Multiply them to get total square footage. For irregular shapes, divide the area into rectangles, calculate each one, and add them together.
Square Feet = Length (ft) x Width (ft)
Step 2: Determine Coverage Width
The coverage width depends on the profile of the boards you are using. Here are common profiles and their typical coverage widths:
Step 3: Calculate Linear Feet Needed
Linear Feet = (Square Feet x 12) / Coverage Width (in inches)
Example: 300 sq ft room with 1x6 T&G (5-1/8" coverage)
(300 x 12) / 5.125 = 702.4 linear feet
Pro tip: To convert linear feet to board feet for pricing purposes, multiply linear feet by the board's nominal width (in inches) divided by 12, then by the nominal thickness (in inches). For our 1x6 T&G example: 702.4 LF x (6/12) x 1 = 351.2 board feet.
Tips for Ordering the Right Quantity
Running short mid-project is costly and frustrating — especially with reclaimed lumber, where matching a specific batch later may be difficult. On the other hand, over-ordering wastes money. Here is how to find the right balance.
Apply the Right Waste Factor
Every installation generates some waste from end cuts, fitting around obstacles, and the occasional damaged board. The standard waste factors for reclaimed lumber are:
- Flooring (straight lay): Add 10% waste factor
- Flooring (diagonal or herringbone): Add 15-20% waste factor
- Wall paneling: Add 10% waste factor
- Siding: Add 12-15% waste factor
- Framing / structural: Add 5-8% waste factor
- Furniture / cabinetry: Add 20-25% waste factor
Why Reclaimed Needs a Higher Waste Factor
Reclaimed lumber naturally has more variation than new stock. Some boards will have nail holes in inconvenient locations, checks that require trimming, or end splits that need to be cut off. These are not defects — they are part of the material's character — but they do affect usable yield.
We recommend adding an extra 5% on top of the standard waste factors listed for new lumber when working with reclaimed stock. For example, if new flooring requires a 5% waste factor, use 10% for reclaimed. If new diagonal flooring calls for 10%, use 15-20% for reclaimed.
Order from One Batch
Reclaimed lumber varies from batch to batch in color, patina, and exact dimensions. Ordering all the material for a project at once ensures visual and dimensional consistency across your installation. If you need to re-order later, we will do our best to match, but an exact match is never guaranteed.
Store Extra Material Properly
Keep 5-10% of your order as spare material for future repairs. Store it flat, stickered for airflow, in a climate-controlled space. Reclaimed wood stored this way will remain stable for years. This small reserve saves enormous hassle if a board is damaged during installation or years later.
Talk to Us Before Ordering
Our team has helped with hundreds of projects and can help you dial in the right quantity. Send us your project dimensions, chosen species, and intended application, and we will provide a detailed material estimate — including waste factor — at no charge. It is better to ask up front than to scramble later.
Pro tip: When ordering reclaimed lumber, always specify whether you need nominal or actual dimensions. Our team can help you find the right sizing for your project.