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Whether you’re building a deck, putting up a fence, or framing a new structure, using our board feet calculator will quickly determine how much lumber to buy before you head to the store, saving time, money, and a second trip. Enter your board dimensions, quantity, and a waste factor below and we’ll calculate your total board feet, adjusted for waste, and give you an estimated cost.
Board Feet Calculator
🪵 Board Feet Calculator
Calculate lumber for decks, fences, and framing projects
Estimates only. Always confirm with your lumber supplier before purchasing.
What Is a Board Foot?
A board foot is a unit of lumber volume equal to a piece of wood 1 inch thick, 12 inches wide, and 12 inches long — or 144 cubic inches in any other combination. It’s the standard unit lumber yards use to price and sell wood, so knowing your board feet is the starting point for any lumber estimate.
How to Calculate Board Feet
The formula is straightforward: multiply the thickness (in inches) × width (in inches) × length (in feet), then divide by 12. For example, a 2×6 board that’s 10 feet long works out to (2 × 6 × 10) ÷ 12 = 10 board feet. The calculator above handles all of this automatically — just enter your dimensions and quantity.
How Much Waste Should I Add?
Always add a waste factor to your lumber estimate. For a straightforward deck or fence with standard cuts, 10% is typical. If your project involves angled cuts, a herringbone pattern, or a lot of notching, bump it to 15–20%. Running short on lumber mid-project is far more frustrating than having a few extra boards left over.
Board Feet vs. Linear Feet — What’s the Difference?
Linear feet measures length only — useful for things like trim, molding, or fence rails where thickness and width are fixed. Board feet measures volume, which accounts for thickness and width too. When buying dimensional lumber like 2×4s or 2×6s for a deck or fence, board feet gives you the complete picture of how much material you actually need.
Tips for Buying Lumber for Deck and Fence Projects
Buy all your lumber from the same lot at the same time if possible — wood color and grain can vary between batches, and mismatched boards are obvious once stained. Let pressure-treated lumber dry for at least 2–3 weeks before staining or sealing, otherwise the finish won’t penetrate properly. And always apply a wood conditioner before staining — it helps the stain absorb evenly, especially on softer woods like pine.