Board Foot Calculator
Free board foot calculator to measure lumber volume. Calculate board feet for any wood dimensions, estimate costs, and plan projects.
Common Lumber Sizes
Dimensional Lumber (Nominal Sizes)
Hardwood Lumber (Actual Sizes)
Enter Dimensions
Optional: Enter price per board foot to calculate total cost
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Calculate Lumber Board Feet Instantly
Need to know how much lumber to buy? Our board foot calculator helps woodworkers, carpenters, and DIYers calculate the exact amount of lumber needed for any project. Enter your dimensions to get board feet, cubic measurements, and cost estimates in seconds.
What is a Board Foot?
A board foot (BF) is the standard unit for measuring and pricing lumber in North America. One board foot equals 144 cubic inches—equivalent to a piece of wood 12 inches long × 12 inches wide × 1 inch thick. Lumber yards, sawmills, and woodworking shops use board feet to price and sell rough lumber, hardwoods, and specialty woods. Understanding board feet helps you compare prices and calculate exactly how much wood you need.
Board Foot Formula
Board Feet = (Thickness × Width × Length) ÷ 12How to Calculate Board Feet
Select a common lumber size preset or enter custom dimensions.
Enter the thickness in inches (nominal or actual).
Enter the width in inches.
Enter the length in feet or inches.
Specify the number of pieces you need.
Optionally enter price per board foot for cost estimate.
View total board feet and cost instantly.
Common Uses for Board Foot Calculations
Woodworking Projects
Calculate lumber needs for furniture, cabinets, and craft projects.
Deck Building
Estimate board feet for deck boards, joists, and framing lumber.
Hardwood Purchasing
Buy rough-sawn hardwood lumber priced by the board foot.
Lumber Yard Shopping
Convert between linear feet and board feet for accurate purchases.
Construction Estimating
Calculate framing lumber for walls, floors, and roofs.
Sawmill Operations
Measure and price lumber output from logs.
Why Use a Board Foot Calculator?
Accurate Lumber Estimates
Know exactly how many board feet you need before visiting the lumber yard.
Cost Planning
Calculate material costs by multiplying board feet by price per BF.
Compare Lumber Prices
Board feet provide a standard unit to compare prices across different sizes.
Reduce Waste
Buy the right amount of lumber to minimize waste and save money.
Project Budgeting
Estimate total wood costs for furniture, decks, and construction projects.
Board Foot Calculator FAQ
Board feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12. For example, a 2×6 that is 8 feet long: (2 × 6 × 8) ÷ 12 = 8 board feet. If length is in inches, divide by 144 instead of 12.
Nominal sizes (like 2×4) are the name of the lumber, while actual sizes are the real dimensions after drying and planing. A nominal 2×4 is actually 1.5" × 3.5". Lumber yards typically use nominal dimensions for board foot calculations, which is industry standard.
Using nominal dimensions: (2 × 4 × 8) ÷ 12 = 5.33 board feet. A standard 8-foot 2×4 contains about 5.33 board feet of lumber.
Multiply linear feet by the cross-sectional area in square inches, then divide by 12. For a 2×6: Linear feet × (2 × 6) ÷ 12. So 10 linear feet of 2×6 = 10 × 12 ÷ 12 = 10 board feet.
Board feet provide a fair way to price wood of varying dimensions. Unlike dimensional lumber sold by the piece, hardwoods come in random widths and lengths. Pricing per board foot ensures you pay for actual wood volume regardless of board size.
Hardwood thickness is expressed in quarters of an inch. 4/4 = 1 inch thick, 5/4 = 1.25 inches, 6/4 = 1.5 inches, 8/4 = 2 inches. These are rough-sawn dimensions—after planing, 4/4 stock yields about 13/16" finished thickness.
Log scaling uses special rules like the Doyle, Scribner, or International scale. These formulas estimate board feet yield accounting for saw kerf, taper, and waste. The Doyle rule is: BF = (D-4)² × L ÷ 16, where D is small-end diameter in inches and L is length in feet.
MBF (thousand board feet) or MFBM (thousand feet board measure) equals 1,000 board feet. Lumber mills and wholesalers use these units for large quantities. If lumber costs $800/MBF, that's $0.80 per board foot.