Total the board feet and the cost for a whole cut list at once — with the 4/4-to-16/4 quarter system hardwood is actually sold by, quantities, a price per board foot, and a waste allowance.
Measurement system
Length entered in
Thickness & width in
Length in
ThicknessWidth (in)Length (ft)QtyBd ft
Board feet are figured on the rough nominal thickness you select. Yards differ on minimums, surfacing charges and rounding — treat this as an order estimate, not a quote.
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Planning the build around the lumber?
The Wood Movement Calculator shows how much your boards will shrink or swell across the seasons, and the Miter and Crown Molding angle calculators give the saw settings for the joints.
What a board foot actually is
A board foot is a unit of volume: 144 cubic inches of lumber, the same as a piece 1″ thick × 12″ wide × 1′ long. Because it captures thickness, width and length together, it’s how rough hardwood is priced — unlike a linear foot (length only) or a square foot (area only).
Rough hardwood is sold in quarter-inch thickness steps written as “quarters.” The yard prices the board on this rough size — what you pay for — even though a surfaced board ends up thinner.
Called
Rough thickness
Typical surfaced (S2S)
4/4
1″
~13/16″
5/4
1¼″
~1 1/16″
6/4
1½″
~1 5/16″
8/4
2″
~1 3/4″
12/4
3″
~2 3/4″
16/4
4″
~3 3/4″
Use the rough figure (the quarter) for the board-foot count. The surfaced dimension matters for fitting parts in your project, not for the invoice.
Why add a waste allowance
The board feet in your finished parts is never the board feet you need to buy. Saw kerf, planer snipe, defects, knots, end checks and the occasional mistake all eat material, and matching grain across a piece wastes more. A common rule is to add 15–30% over the net amount — the low end for clean, straightforward dimensional cuts, the high end for rough or figured stock and grain-matched work. Enter your percentage and it’s added to both the feet and the cost.
Board feet vs the other “feet”
Board foot — volume (144 in³). How hardwood is sold.
Linear foot — length only. How trim, moulding and dimensional softwood are often sold.
Square foot — area. How sheet goods and flooring are sold.
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Frequently asked questions
How do you calculate board feet?
A board foot is 144 cubic inches — a piece 1″ thick, 12″ wide and 1′ long. Multiply thickness″ × width″ × length″ and divide by 144; if length is in feet, divide by 12 instead. Multiply by the quantity of identical boards. This calculator sums every line of your cut list into one total.
What do 4/4, 5/4 and 8/4 mean?
Rough hardwood is sold in quarter-inch thickness steps written as quarters: 4/4 is 1″, 5/4 is 1¼″, 6/4 is 1½″, 8/4 is 2″, up to 16/4 at 4″. Board feet are figured on this rough nominal thickness — what you pay for — even though a surfaced 4/4 board finishes around 13/16″.
Nominal or actual thickness for board feet?
Use the rough nominal thickness it’s sold as (the quarter figure). The yard prices the board on its rough size before surfacing, so that’s what you’re charged for. The thinner surfaced dimension matters for fitting your parts, not for the board-foot count. Dimensional softwood like 2x4 is a separate convention, usually priced by the piece or linear foot.
How much waste should I add?
Most woodworkers add about 15–30% over the net board feet for kerf, defects, snipe, thicknessing and mistakes. Use the low end for clean dimensional cuts, the high end for rough, figured or grain-matched stock. Enter your allowance and it’s applied to both feet and cost.
Is a board foot the same as a linear or square foot?
No. A linear foot is length only; a square foot is area. A board foot is volume — 144 cubic inches — so it includes thickness, width and length. Hardwood sells by the board foot; trim and moulding often by the linear foot; sheet goods by the square foot or sheet.