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Lumber Cut-List Optimizer
List the pieces your project needs, pick a stock board length and blade kerf, and get the minimum number of boards to buy with your total waste percentage.
A simple, practical bin-packing method
This optimizer sorts every piece you need from longest to shortest, then places each one on the first stock board that still has enough room left, opening a new board only when none of the boards already in progress can fit it. It's known as first-fit decreasing — fast to compute and, in practice, usually very close to the true minimum number of boards.
Kerf adds up fast
Every cut takes a bite out of the board equal to the blade's kerf, on top of the piece length itself. Across a whole cut list that can easily add several centimetres of extra material used per board, which is exactly why it's factored into both the board count and the waste percentage here rather than left as an afterthought.
Frequently asked questions
How does the optimizer decide which pieces go on which board?
It uses a first-fit decreasing approach: pieces are sorted from longest to shortest, and each one is placed on the first board that still has enough room, opening a new board only when none of the current boards can fit it. It's a fast, practical method, not a perfect mathematical optimum, but it's usually very close.
Why include the saw kerf in the calculation?
Every cut removes a thin slice of material equal to the blade's width, so the board gets shorter by the kerf with every cut, not just by the length of the pieces. Ignoring it is a common reason a cut list that looked fine on paper comes up short on the last piece.
What counts as waste in the waste percentage?
Waste is the total stock length bought minus the total usable piece length needed, including kerf losses and the offcuts left over at the end of each board. A lower percentage means the stock lengths you chose are being used more efficiently.
Should I always buy the exact number of boards this shows?
Treat it as the practical minimum assuming clean, defect-free stock. It's worth buying at least one extra board for any project, since real lumber has knots, warp or damaged sections that can make a piece unusable.