How to use it
Working out an order
Enter one piece
Thickness and width in inches, length in feet — the size the seller tallies by: usually the rough quarter thickness for hardwood (4/4 = 1 in) and the nominal size for softwood (a 2 × 4 is entered as 2 × 4).
Enter how many pieces the project needs
Whole pieces of that size. For a mixed list, run each size separately, or lay the parts out first with the cut list optimizer.
Add a waste allowance
A percentage for defects, end checks and mistakes. The calculator multiplies and rounds up to whole pieces: 10 pieces plus 10% is 11, plus 15% is 12.
Optional: enter the price
Choose the basis the seller quotes — per board foot, per linear foot or per piece — and type the price. Only that basis is used for the cost.
The formulas
Pieces, volume, length and cost
pieces to buy = ⌈ pieces needed × (1 + waste % ÷ 100) ⌉
bd ft = T × W × L(ft) ÷ 12 × pieces to buy
lin ft = L(ft) × pieces to buy
cost = price × (bd ft, lin ft or pieces to buy)
price per bd ft = cost ÷ bd ft
- T
- thickness (in)
- W
- width (in)
- L
- length of one piece (ft)
- ⌈ ⌉
- round up to a whole number
A board foot is a volume, 144 cubic inches; a linear foot is a length. They convert into each other only through the piece's thickness and width, which is why the calculator asks for them.
| Order | Pieces to buy | Board feet | Linear feet | Cost |
|---|---|---|---|---|
| 10 × (1 in × 6 in × 8 ft), 10% waste, at 5 per bd ft | 11 | 44 | 88 | 220 (5 per bd ft) |
| 3 × (1-1/2 × 3-1/2 in × 8 ft), no waste, at 0.90 per lin ft | 3 | 10.5 | 24 | 21.60 (2.06 per bd ft) |
| 7 × (3/4 × 5-1/2 in × 6 ft), 15% waste, at 12 per piece | 9 | 18.56 | 54 | 108 (5.82 per bd ft) |
Prices are illustrative inputs, in no particular currency, not market figures. These rows are among the calculator's test cases.
Board feet, linear feet, square feet
- Board feet measure volume: 1 in × 12 in × 12 in. Hardwood is usually sold this way.
- Linear feet measure length only, whatever the width and thickness: a price per linear foot means nothing until you know the size it is for.
- Square feet measure area, for sheet goods and flooring. This calculator does not use them; for sheets see the plywood calculator, and to turn board feet into square feet at a thickness, the converter on the board foot calculator.
- Comparing quotes. Two prices on different bases can only be compared at the same piece size; the 'per board foot' restatement does that for the size you entered.
Assumptions and limits
- Tally size. Softwood is usually counted by nominal size and hardwood by rough thickness; if your seller tallies differently, enter their numbers. Actual sizes are on the lumber dimensions chart.
- Whole pieces. The calculator buys whole pieces of the length you enter. It does not plan cuts; the cut list optimizer does.
- Random widths. Hardwood often comes in mixed widths. Use an average width for an estimate, and let the yard's tally decide the bill.
- No prices supplied. BenchRoot does not publish lumber prices; the cost is only as good as the price you enter.
- Not a building estimator. It does not size framing, decks or walls; it counts and prices the pieces you specify.
Before ordering lumber
- Piece size entered as the seller tallies it
- Pieces counted from a cut list, not guessed
- Waste allowance chosen for the grade and your skill
- One price basis, the one in the quote
- Quotes compared per board foot at the same size
- Moisture content and grade written on the order
Grades and sizes to put in the order are in the lumber guide and the grain to look for in wood grain; the whole buying decision is in choosing lumber.
Sources
The formulas follow from the definitions of the board foot and the linear foot. No prices are supplied: the calculator uses only the price you enter, on the basis you choose.
- 1.
NIST Handbook 130 (2026), IV.B Uniform Regulation for the Method of Sale of Commodities. National Institute of Standards and Technology, 2026.
Used for: The board foot as a volume of 144 cubic inches (1 ft × 1 ft × 1 in); softwood nominal and dressed sizes under PS 20.
- 2.
Chapter 6: Commercial Lumber, Round Timbers, and Ties. USDA Forest Service, Forest Products Laboratory — Wood Handbook, FPL-GTR-282, 2021.
Used for: Hardwood sold by rough thickness in quarters with S2S thicknesses smaller (Table 6–4); random widths; lengths in 1-ft steps.
About this calculator
Written by BenchRoot Editorial. How BenchRoot sources, checks and corrects its pages is set out in the Editorial Policy. If something here is wrong or unclear, the contact page explains how to tell us.