Lumber / Board-Foot Calculator
Calculate board feet from a board's thickness, width, and length, multiply by quantity, and get a total cost at your price per board foot — the standard way hardwood and rough lumber are sold and quoted.
How to Use
- Enter the board thickness and width in inches and the length in feet for one piece.
- Enter how many identical pieces you are buying.
- Enter your price per board foot to get a running cost.
- Read the board feet per piece, the total board feet, and the total price.
- Check the Show Work below to see the (T × W × L ÷ 12) board-foot math.
Show Work
Formula
About the Lumber / Board-Foot Calculator
Lumber / Board-Foot Calculator is a quick, free tool for building, materials estimation and site work. It works in your browser and keeps everything on your device. Calculate board feet from a board's thickness, width, and length, multiply by quantity, and get a total cost at your price per board foot — the standard way hardwood and rough lumber are sold and quoted.
How it works
Enter your figures and the result appears instantly, updating the moment you change anything. There is no submit button and nothing to wait for, so it is easy to try a few what-if numbers and compare the results. Just check each box holds the kind of value it expects.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
What is a board foot?
A board foot is a volume unit equal to 144 cubic inches — a piece 1 inch thick, 12 inches wide, and 1 foot long. Hardwood and rough lumber are priced by the board foot rather than by the piece. The formula is thickness (in) × width (in) × length (ft) ÷ 12.
Should I use nominal or actual dimensions?
Board-foot pricing traditionally uses nominal (called) dimensions — a 2×4 is figured as 2" × 4" even though it actually measures about 1.5" × 3.5" after surfacing. This calculator follows that convention. For rough-sawn hardwood, the nominal and actual sizes are much closer, so the number is more literal.
How is board foot different from a linear foot?
A linear foot just measures length and ignores the cross-section, while a board foot accounts for thickness and width too. Two boards the same length can differ greatly in board feet if one is thicker or wider. Dimensional softwood is often sold by the piece or linear foot, but hardwood is almost always by the board foot.
How do I price a hardwood project?
Add up the board feet of every part, then multiply by the per-board-foot price for that species and grade — and add 15–30% for waste, because you cannot use every inch around knots, checks, and cutoffs. This tool gives you the board feet and cost per cut size so you can total a cut list.
What does a quarter (4/4, 8/4) mean in lumber?
Hardwood thickness is sold in quarters of an inch, so 4/4 ("four-quarter") is nominally 1 inch thick, 8/4 is 2 inches, and so on. That is the rough thickness before surfacing — a 4/4 board planed smooth ends up around 13/16". Use the nominal quarter thickness in the thickness field here.
How do I use the Lumber / Board-Foot Calculator?
Just type your numbers. The answer shows up right away — there is no button to press. Change anything and it updates by itself.
Does it cost anything or need an account?
No. The tool is completely free, there is no account to create, and it keeps working offline after the page first loads.
Is anything I type uploaded?
No. The tool works entirely on your device, so the values you enter never leave your browser.
Common Use Cases
Pricing a hardwood order
Convert each board size and quantity into board feet and a total cost at your supplier's rate.
Totaling a cut list
Run each part of a furniture or trim project to add up the board feet you need to buy.
Comparing lumber quotes
Normalize per-piece prices to a per-board-foot basis so you can compare yards fairly.
Estimating framing material cost
Multiply dimensional lumber like 2×4s and 4×4s by quantity to budget a framing package.
Buying rough-sawn stock
Figure board feet for 4/4 or 8/4 rough lumber so you order enough to mill down with waste.
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