Board Foot Calculator

Last updated: April 5, 2026

The Board Foot Calculator converts lumber thickness, width, and length into board feet — the volumetric unit used to price lumber at sawmills, hardwood dealers, and specialty yards. One board foot equals 144 cubic inches of wood. Enter any lumber dimension and get your board feet instantly.

Calculator

Thicknessin

Widthin

Lengthft

Quantity

Waste Allowance%

Price per Board Foot$/BF

Results

Board Feet

Board Feet with Waste

4.4

Total Volume

0.333

ft³

Estimated Material Cost

Results

Board Feet

Board Feet with Waste

4.4

Total Volume

0.333

ft³

Estimated Material Cost

Board feet sounds technical but the formula is simple: multiply thickness (inches) × width (inches) × length (feet) and divide by 12. The result is the volume of your board measured in board feet — the unit your lumber dealer quotes when you ask for a price. The board foot calculator handles this arithmetic for any single piece and explains when you need board feet vs. linear feet vs. square feet.

The Board Foot Formula

Board Feet = Thickness (in) × Width (in) × Length (ft) ÷ 12

Common examples:

1" thick, 4" wide, 10 ft long: 1 × 4 × 10 ÷ 12 = 3.33 BF
1" thick, 8" wide, 8 ft long: 1 × 8 × 8 ÷ 12 = 5.33 BF
2" thick, 6" wide, 12 ft long: 2 × 6 × 12 ÷ 12 = 12 BF
2" thick, 10" wide, 16 ft long: 2 × 10 × 16 ÷ 12 = 26.67 BF

Use this online calculator for any single piece. The board feet calculator handles full project cut lists with multiple different pieces.

When to Use Board Feet vs. Other Units

Board feet: hardwood lumber, specialty sawmill lumber, pricing structural timber by volume
Linear feet: trim, moulding, baseboards, crown — products where you pay for length and the cross-section is standardized
Square feet: flooring, plywood sheets, OSB sheathing — products covering an area
Piece price: dimensional framing lumber at big-box stores (2×4, 2×6, etc.) is usually sold by the piece at set lengths

The distinction matters when comparing quotes: a yard quoting 'USD 3/BF' for a 2×6 and another quoting 'USD 1.50/LF' are not necessarily equivalent — you need the BF-to-LF conversion to compare them.

Hardwood Quarter-Inch Thickness Reference

Hardwood lumber thickness uses the quarter system: 4/4 = 1" rough; 5/4 = 1.25"; 6/4 = 1.5"; 8/4 = 2"; 10/4 = 2.5"; 12/4 = 3". Board feet calculations use the rough-sawn nominal thickness, not the surfaced actual thickness. The board and batten calculator and lumber calculators cover additional project planning tools.

Visual Analysis

How It Works

Enter board thickness in inches, width in inches, and length in feet (or inches, automatically converted). Board feet = thickness × width × length(ft) ÷ 12. For multiple pieces of the same dimensions, multiply the result by piece count. The calculator also displays the raw cubic inches (thickness × width × length in inches) for reference.

Worked Examples

Example 1

Inputs

Results

Example 2

Inputs

Results

Frequently Asked Questions

Using nominal dimensions: 2 × 4 × 8 ÷ 12 = 5.33 board feet. Using actual dimensions (1.5" × 3.5"): 1.5 × 3.5 × 8 ÷ 12 = 3.5 board feet. The nominal volume is 5.33 BF; the actual wood you receive is 3.5 BF — 34% less. Most softwood dimensional lumber at big-box stores is sold by the piece (e.g., 'USD 6.99 per 2×4×8 stud') not by board foot, so the distinction matters most when ordering from lumber yards that price by BF. For hardwood purchases, actual dimensions are used; for standard construction softwood pricing by BF, nominal dimensions are usually applied.

Linear feet counts only the length of a board, ignoring thickness and width — 8 linear feet of 1×4 and 8 linear feet of 2×8 are the same in linear feet but very different in board feet (2.67 BF vs. 10.67 BF). Board feet accounts for all three dimensions, giving a true volume comparison. Use linear feet when you need to cover a specific run (trim, moulding, fascia). Use board feet when you are paying for the actual amount of wood by volume (hardwood purchases, structural timber). Confusing the two when comparing quotes is a quick way to pay 3–4× more than you expected.

Linear feet = board feet × 12 ÷ (thickness in inches × width in inches). For a 1×6 board: LF = BF × 12 ÷ (1 × 6) = BF × 2. So 10 BF of 1×6 = 20 linear feet. For a 2×8: LF = BF × 12 ÷ (2 × 8) = BF × 0.75. So 20 BF of 2×8 = 15 linear feet. This conversion is essential when a dealer quotes you a price per BF but you need to estimate coverage (how many feet of railing, how many rows of paneling, etc.).

4/4 (four-quarter) lumber is 4 quarters of an inch = 1 inch nominal rough-sawn thickness. The board foot calculation for 4/4 lumber uses the nominal 1-inch thickness: a 4/4 board 6 inches wide and 8 feet long = 1 × 6 × 8 ÷ 12 = 4 BF. After surfacing (planing smooth on 2 sides, called S2S), actual thickness is typically 13/16" to 7/8" — but you pay for the 4/4 (1") BF volume. The surfacing loss is built into hardwood pricing. Higher thicknesses: 8/4 = 2" rough (price calculated on 2" thickness), typically surfaces to about 1.75".

List every part: thickness × width × length. Calculate BF per part using the formula; multiply by piece count; sum all parts. Add your waste factor (10–15% for simple work; 20–25% for fine furniture with joinery and figure selection). Example: small bookcase — shelves: 4 × (0.75" × 11.25" × 36") = 4 × (0.75 × 11.25 × 3) ÷ 12 = 4 × 2.11 = 8.44 BF; sides: 2 × (0.75" × 11.25" × 48") = 2 × 2.81 = 5.63 BF; total 14.07 BF + 25% waste = 17.6 BF to order. At USD 8/BF for cherry, total material cost = approximately USD 141 before any other supplies.

No — board foot pricing applies primarily to hardwood and specialty lumber. Standard dimensional construction softwood (2×4, 2×6, 2×8 in spruce, pine, or fir) is almost always sold by the piece at set lengths at big-box stores and most framing lumber yards. Sheet goods (plywood, OSB, MDF) are sold by the sheet (4×8 = 32 sq ft). Moulding and trim are sold by the linear foot. Hardwood flooring is sold by the square foot. Timber framing material may be sold by the board foot or by the piece depending on the supplier. When you call a lumber yard for pricing, always ask 'is that per board foot, per linear foot, or per piece?' to avoid conversion errors.

Sources & Methodology

NHLA (2023). Rules for Measurement and Inspection of Hardwood and Cypress. USDA Forest Products Laboratory (2021). Wood Handbook. American Lumber Standard Committee (2023). Voluntary Product Standard PS 20.

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