Buying hardwood for the first time is mildly disorienting. The timber isn’t stacked in tidy standard sizes, the price is quoted in a unit that doesn’t appear anywhere else in daily life, and the thickness is described in quarters.
None of it is complicated once unpacked. But when you’re standing in front of a stack trying to work out whether you’re being offered a fair price, doing the arithmetic in your head for a dozen boards is not where you want to be.
Enter your boards — quantity, thickness, width, length — and the tool totals the board feet for the whole list. Add a waste percentage and it tells you how much to actually order; add a price per board foot and it costs the job.
It works in imperial or metric, and includes two reference tables that are genuinely useful at the timber yard: hardwood quarter thicknesses, and nominal versus actual sizes for dimensional lumber.
Take a single board, 1 inch thick, 6 inches wide and 8 feet long:
(1 × 6 × 8) ÷ 12 = 4 board feet
Buy four of those and you have 16 board feet, whether they came from one tree or four. With a 15% waste factor applied, you’d order 18.4 board feet — and if the timber were priced at £12 per board foot, that’s the number the cost is calculated from, not the 16 you’ll actually use.
That distinction is the practical value of the waste factor. Ordering exactly your calculated requirement is a reliable way to come up short partway through a build, usually on the last part, late in the day.
Worth knowing before you order: hardwood grades describe how much clear, defect-free wood a board will yield, not how strong it is. For small parts — which describes box making almost exactly — a lower grade is often the smarter buy. No. 1 Common gives you the same clear timber as FAS, just in smaller pieces, at a lower price. Paying a premium for long clear boards and then cutting them into 8-inch parts is paying for something you’re about to saw away.
FAS earns its price when you genuinely need the length and the width. The board foot guide below goes into the grading system properly…
A board foot is a unit of volume, not length — 144 cubic inches of wood. One board foot is what you'd get from a piece 1 inch thick, 12 inches wide and 12 inches long. Change any of those dimensions and the piece can still be one board foot, as long as the total volume works out the same.
Thickness × width × length in inches, divided by 144. If your length is in feet, which is how timber is usually sold, the shortcut is thickness × width in inches × length in feet, divided by 12. A board 1 inch thick, 6 inches wide and 8 feet long is (1 × 6 × 8) ÷ 12 = 4 board feet.
It's thickness counted in quarter-inch steps. 4/4 — said 'four-quarter' — is four quarters of an inch, so 1 inch. 8/4 is 2 inches. Rough lumber has historically been specified that way at the sawmill. Note that it describes the rough-sawn board, not the finished thickness after planing, so a 4/4 board typically finishes a little under a true inch.
Somewhere in the 15–20% range is a common starting point for a straightforward project. Saw kerf, defects, snipe, and grain matching all consume timber without contributing to the finished piece. Push it higher for knotty or figured stock, or where you're matching colour and grain across several visible parts.
Because hardwood is generally sold random width and length, so you're buying from whatever's in the stack rather than ordering standard sizes. Two boards the same length can contain very different amounts of wood — an 8-inch wide board has twice the timber of a 4-inch one. Pricing by volume charges for what's actually there.