Board-foot calculator
Add each board you need and get the total board feet for your lumber order.
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One board foot is 144 cubic inches (a 1″ × 12″ × 12″ board). Enter rough dimensions for buying lumber; actual usable size will be less after milling. Name each board (e.g. “Legs”) and set a price per board foot to estimate cost, mix species at different prices. A waste allowance inflates your buy quantity to cover jointing, planing, and cut-offs (first-time buyers typically need 20%). Cost is an estimate; real lumber prices vary by grade, region, and supplier. Board footage is always shown as a total regardless of the unit you enter dimensions in, since lumber yards sell by the board foot either way.
What is a board foot?
A board foot is a unit of lumber volume equal to 144 cubic inches, the same amount of wood as a piece that is 1″ thick × 12″ wide × 12″ long. It’s how lumber yards price wood in bulk, so calculating your board feet before you visit the yard prevents under-buying and over-spending.
Rough vs. surfaced dimensions
Lumber is sold by its rough (nominal) dimensions, the size before it was milled flat. A “1-inch” board actually measures about ¾″ after surfacing; a “2×4” is really 1½″ × 3½″. Always use rough dimensions when estimating board feet so your count matches what the yard charges you.
How to measure a rough board
- Thickness, measure across the thinnest face in inches. Round up to the nearest standard thickness (¾″, 1″, 1¼″, 1½″, 2″).
- Width, measure the widest face. For a waney-edge (live edge) board, measure at the widest point and expect some waste.
- Length, measure in inches end to end.
- Add a 10–15% waste allowance to your total for jointing, planing, and cut-offs. First-time buyers typically need 20%.
Tip for beginners
If you’re not sure which species to buy, check the species reference and filter by Beginner-friendly. Poplar and soft maple are forgiving, inexpensive, and available at most hardwood dealers.
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