Board Foot & Lumber Cost Calculator
Enter dimensions and quantity to get board feet and cost at your own price per board foot — the state lives in the URL, so you can copy the link and come back to the same result.
How this works
The calculator above takes thickness, width and length in inches, plus quantity, and computes board feet using the standard definition — one board foot equals 144 cubic inches, so board feet = (thickness x width x length) / 144 for a single piece, multiplied by quantity for the line item. That's the entire formula; there's no rounding convention or lumberyard-specific fudge factor hidden inside it, and the board feet, explained properly post walks through the full derivation and the three most common ways people get the number wrong by hand.
How to read the result
The board-foot figure is a volume, not a price — multiply it by your price per board foot (the second number you enter) to get a material cost estimate. That cost is for the quantity you specify, not per piece, so raising the quantity field scales the total linearly: two identical pieces cost exactly twice what one does, because they contain exactly twice the wood.
Nominal vs. actual dimensions — the input that trips people up
Enter the board's actual, measured dimensions, not the nominal size printed on a price tag or a cut list. A "2x4" measures 1.5" x 3.5" actual; entering "2" and "4" into the thickness and width fields will overstate the true board-foot count by roughly a third. See /reference/nominal-vs-actual-2x4/ for the full nominal-to-actual table across common dimensional lumber sizes, and measure your own stock with a tape measure if there's any doubt — rough hardwood in particular varies board to board.
Why the URL changes as you type
Every value you enter is written into the page's URL as you go, so the exact combination of dimensions, quantity and price you're looking at is always a link you can copy, bookmark, or send to someone else — reload the page from that link later and the same numbers, and the same result, come back. That's deliberate: a calculator result that can't be linked to is a result nobody else can check.
What it doesn't account for
This calculator computes the board feet and cost of the wood itself — it does not add waste, kerf loss from cutting, or defect allowance. For a full project's worth of pieces cut from real stock boards, factoring in saw kerf and minimizing offcuts, use the cut list optimiser once you know the exact pieces the project needs; /reference/lumber-yield-and-waste-factor-guide/ covers typical waste percentages to budget on top of a raw board-foot total before you place an order.