Know your lumber bill before you drive to the yard.
Zero Kerf is a free board foot calculator that plans the whole project: every part, every
species, waste, tax, cost, and weight. No account, no ads — your projects stay on your
device, and a share link carries the whole plan inside the URL.
List parts, not math
Enter each part the way you think about it — four legs, 8/4, 3 by 18 — and the board
feet, cost, and a to-scale drawing of every piece update as you type.
Your prices, remembered
Thirty species come pre-loaded with dated price estimates. Change any price to what your
lumberyard actually charges and Zero Kerf uses yours from then on.
Works at the lumberyard
Install it on your phone's home screen and it works with no signal. Print the cut list
or share the project as a link that needs no login to open.
A board foot is a volume: 144 cubic inches of rough lumber — one inch
thick, a foot wide, a foot long. Hardwood sells by the board foot because boards come off
the saw in random widths and lengths.
board feet = thickness″ × width″ × length″ ÷ 144
Worked example: a 4/4 walnut board, 6″ wide and 8 feet long, is
1 × 6 × 96 ÷ 144 = 4 BF. At $9.50 per board foot that piece costs
$38.00.
Two things trip people up. First, board feet use the rough thickness — a 4/4
board counts as a full inch even though it surfaces to about 13/16″; see
nominal vs actual sizes. Second, you can't buy
exactly what the math says: plan 15–20% waste for defects, milling, and mistakes — the
planner above does this for you.
What is a board foot?
A volume of lumber equal to 144 cubic inches — a piece 1″ thick, 12″ wide, and 12″ long.
Thickness × width × length (all in inches) ÷ 144 gives board feet for any board.
How do I calculate board feet?
Multiply thickness by width by length in inches and divide by 144. A 4/4 board 6″ wide
and 96″ long: 1 × 6 × 96 ÷ 144 = 4 board feet.
Do I use nominal or actual thickness?
Nominal (rough) thickness. A 4/4 board counts as 1″ thick even after it's surfaced to
13/16″ — you pay for the wood before milling.
How much waste should I plan for?
15–20% covers defects, checking, milling loss, and honest mistakes for most projects.
Figured or knotty stock can run 30% or more.