Board foot calculator (lumber)
Convert your lumber dimensions into board feet — the unit hardwood and rough lumber are priced in. Enter the nominal thickness, width, length, and how many boards. One board foot is 144 cubic inches (1 ft × 1 ft × 1 in).
88.0 bd ft
Board feet
- Per board
- 8.00 bd ft
- Total linear feet
- 80 ft
What this assumes
- Board feet = (2 in × 6 in × 8 ft ÷ 12) × 10 board(s), +10% overage.
- Uses NOMINAL dimensions — lumber is priced by nominal board feet even though a milled board measures less.
- One board foot = 144 cubic inches (1 ft × 1 ft × 1 in).
Coverage rates & sources
Every number this calculator uses is a published engineering constant — not an estimate we made up. Here is exactly what it assumes and where each value comes from.
- Board foot: 144 in³ (1 ft × 1 ft × 1 in)Source: Lumber industry standard unit of volume (board-foot definition)
- Board-foot formula: thickness(in) × width(in) × length(ft) ÷ 12Source: Algebraic identity from the board-foot definition (144 in³)
Before you buy
- Board feet uses NOMINAL lumber dimensions (a '2×4' counts as 2 in × 4 in) — how lumber is sold and priced — even though a surfaced board is smaller (a 2×4 actually measures 1.5 in × 3.5 in).
- Board feet measures the VOLUME of lumber, not linear feet or surface coverage. For decking area or fencing, use those calculators.
- Hardwood is sold by the board foot; dimensional softwood is often sold per piece — confirm how your supplier prices it.
This is a planning estimate, not a substitute for a pro's on-site measurement. For load-bearing, structural, or code-regulated work, confirm quantities with a licensed contractor.
Frequently asked
Do I use the nominal or actual size for board feet?
Use the nominal size — what lumber is named and sold by. A 2×4×8 is figured as 2 × 4 × 8 for 5.33 board feet, even though the surfaced board measures 1.5 × 3.5 inches. That's the convention suppliers price by.
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