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Board Foot Calculator — Lumber Volume, Cost & Weight for Rough and Surfaced Stock

Quarter-Thickness Sizing (4/4 to 16/4), Cut List Builder, Species Pricing, Waste Factor, and Weight Estimation

Free board foot calculator for woodworkers, lumber buyers, and cabinet makers. Enter board dimensions (thickness, width, length) to calculate board feet for individual boards or a multi-item cut list. Supports quarter-thickness notation (4/4, 5/4, 6/4, 8/4, 10/4, 12/4, 16/4) with automatic conversion to actual rough and surfaced dimensions. Includes species-specific pricing per board foot, waste factor for saw kerf and cutoff loss, and weight estimation based on wood species density and moisture content.

Pro Tip: When buying rough lumber, remember that 4/4 stock is 1" rough-sawn but mills down to 3/4" surfaced (S2S). If your project needs a full 1" finished thickness, you need to buy 5/4 stock. Always measure and calculate board feet yourself at the lumber yard — the seller's tally may include boards you rejected for defects. And never buy exactly the board footage your cut list requires. Add 20-30% for defects, bad ends, grain matching, and saw kerf. On figured or exotic wood, add 40% because you'll want to be selective about which grain goes where.

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Board Foot Calculator

How It Works

  1. Enter Board Dimensions

    Input the board thickness in quarter notation (4/4, 5/4, 6/4, etc.) or decimal inches, width in inches, and length in feet (or inches). The calculator converts quarter notation to actual rough thickness and shows the expected surfaced thickness after planing. For S4S lumber from a big-box store, enter the actual dimensions (e.g., 3/4" x 3-1/2" for a nominal "1x4").

  2. Set Quantity

    Enter the number of boards with those dimensions. The calculator multiplies by quantity to show total board feet for that line item.

  3. Build a Cut List

    Add multiple line items with different dimensions to build a complete project cut list. Each line shows individual board feet and the running total. Group items by species if you're buying from different wood piles.

  4. Apply Waste Factor

    Set a waste percentage (default 20%) to account for saw kerf, defect cutoffs, board end waste, and grain matching. The adjusted total shows how much lumber you actually need to buy. Increase waste factor for knotty or figured wood.

  5. Review Cost and Weight

    Enter a price per board foot for your species to see the estimated material cost. Select a wood species for density-based weight estimation. Common prices: construction pine $2-4/BF, red oak $4-7/BF, hard maple $5-8/BF, walnut $8-14/BF, cherry $6-10/BF. Prices vary significantly by region, grade, and supplier.

Built For

  • Furniture makers estimating lumber costs before starting a project by building a cut list with board footage and pricing
  • Woodworkers at the lumber yard calculating board feet of individual boards to verify the seller's tally
  • Cabinet shops estimating material costs for kitchen and bathroom cabinet jobs with multiple wood species
  • Timber frame builders calculating board footage for large structural members (6x6, 8x8, and larger)
  • Woodturners estimating blank weights and costs for bowl and vessel blanks from exotic species
  • Hobbyist woodworkers budgeting a project by comparing species options (maple vs walnut vs cherry) at current board foot prices

Features & Capabilities

Quarter-Thickness Notation

Enter thickness as 4/4, 5/4, 6/4, 8/4, 10/4, 12/4, or 16/4 — the standard lumber yard notation. The calculator shows both rough thickness (as purchased) and expected surfaced thickness after planing. For example, 4/4 is 1" rough, 13/16" after S1S, and 3/4" after S2S.

Cut List Builder

Build a multi-item cut list with different dimensions, quantities, and species per line item. The calculator totals board feet, cost, and weight across all items. Export the cut list as a PDF or CSV to bring to the lumber yard.

Species Pricing

Enter price per board foot for your species and grade. The calculator estimates total material cost including waste. Price presets for common species (oak, maple, walnut, cherry, pine, poplar, ash) provide starting estimates that you can adjust to your local supplier's current pricing.

Waste Factor

Configurable waste factor (10-50%) adds material for saw kerf, defects, end trim, and grain selection. The adjusted total shows the actual amount to purchase, not just the net finished requirement. Default 20% is appropriate for clear-grade hardwoods; increase for lower grades or figured wood.

Weight Estimation

Estimates weight based on species density and a configurable moisture content (default 8% for kiln-dried). Useful for shipping calculations, workshop floor loading, and knowing what you're trying to lift. Shows weight per board and total cut list weight in pounds and kilograms.

Rough vs Surfaced Conversion

Shows the actual surfaced dimension for each quarter-thickness grade: rough, S1S (one face planed), and S2S (both faces planed). Helps you buy the right thickness to end up with your target finished dimension after milling.

Frequently Asked Questions

A board foot (BF) is a unit of lumber volume equal to 144 cubic inches — a piece 1 inch thick, 12 inches wide, and 12 inches long. The formula is: board feet = (thickness in inches x width in inches x length in inches) / 144. Alternatively: (thickness x width x length in feet) / 12. Lumber yards price hardwood by the board foot. Softwood from big-box stores is typically priced by the linear foot, but the board foot calculation still applies for comparing prices across different sizes.
Quarter-thickness notation (4/4, 5/4, etc.) refers to the rough-sawn thickness before any planing. 4/4 means 4 quarter-inches = 1 inch rough. Planing (surfacing) removes approximately 1/16" from each face, so S2S (surfaced two sides) 4/4 stock ends up at approximately 13/16" or 3/4" thick depending on the mill. If you need a full 1" finished thickness, buy 5/4 stock. This is the single most common mistake when buying lumber for the first time.
For clear-grade (FAS or Select) hardwoods, 20% waste is a safe starting point. This accounts for saw kerf (1/8" per cut), squaring rough-edge boards, cutting around minor defects, and end trim. For #1 Common grade, increase to 30-35%. For knotty or character-grade wood, plan 40% or more. For highly figured wood (curly maple, quilted sapele), plan 40-50% because you'll reject pieces that don't match visually. Better to have leftover wood than to be one board short mid-project.
For a tapered board (wider at one end), measure the width at the narrowest point and at the widest point, then average them. Use the average width in the board foot formula. Lumber yards typically round width down to the nearest whole inch for rough lumber. For highly irregular shapes (live-edge slabs, burls), the standard practice is to estimate the rectangular area that the piece covers and discount by 60-70% to account for the irregular shape and bark loss.
Board footage is calculated from the actual dimensions at the time of purchase, regardless of moisture content. However, green (undried) lumber will shrink as it dries. Hardwood typically shrinks about 4-8% across the grain (width) and minimally along the grain (length) when drying from green to 8% MC. If you buy green 4/4 lumber at 1" thick, it may be only 15/16" thick after kiln drying. Professional lumber dealers account for this in their sawing and drying practices, but if you're buying green or air-dried wood, factor in shrinkage.
Disclaimer: Board foot calculations are based on entered dimensions and standard formulas. Actual lumber dimensions, waste, and pricing vary by supplier, grade, species, and region. Weight estimates use average species densities and may not reflect the specific moisture content or density variation in your lumber. Always verify dimensions and pricing at the point of purchase. ToolGrit is not responsible for material estimation errors or purchasing decisions based on calculator output.

Learn More

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Board Foot Calculator Guide: How to Buy Rough Lumber by the Board Foot

Everything you need to know about buying lumber by the board foot. Covers the board foot formula, quarter-thickness system (4/4, 8/4), rough vs surfaced pricing, waste factors, and species pricing reference.

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