Pieces from the board
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Shop estimate. Measure your stock and cut a test on scrap.
How to use it
- Enter the board length, the finished piece length, and the kerf. Measure the kerf from a test cut in the same blade and the same material if the count is close.
- Enter end trim as a single total. Two square ends mean you add both.
- Read the count, the number of kerfs, and the leftover.
- Leftover smaller than a piece is waste for this cut. It may still be a part somewhere else.
The formula
Count = floor( (usable length + kerf) ÷ (piece + kerf) ). Usable length is the board minus the trim.
- n − 1. The number of kerfs for n pieces. The offcut stays attached until you decide to cut it free.
- Trim. Removed once, before the pieces are counted.
- Leftover. What remains after the pieces and the kerfs between them.
Worked example
An 8 foot board, 1 inch trimmed off the end, cut into 12 inch pieces with a ⅛ inch kerf, yields 7 pieces. The saw makes 6 kerfs between them, not a kerf after the last piece. Leftover stock is 10.25 inches, which is not another 12 inch piece.
If your trim is a square cut on both ends, add both ends into the one trim number. The calculator subtracts that total once, then divides what remains.
What it will not decide
- Identical lengths only. Mixed lengths belong on the linear cut list. Rectangles on a panel belong on the sheet page.
- It assumes the board is straight enough to use the full length you typed.
- It does not price the leftover. The board-foot page can, if you measure it as its own board.
Questions
Why not one kerf per piece?
You need a kerf between pieces. After the last piece, another kerf would only shorten the offcut. Counting that extra kerf makes the yield look worse than the board is.
What kerf should I type?
The width of the groove your blade leaves. A full-kerf table-saw blade is often near ⅛ inch. Thin-kerf blades are narrower, and a dull blade can cut wider than its plate. One test cut is worth more than a catalog number.
Does this work for plywood strips?
Yes, if they are identical and you are crosscutting or ripping a single line of them. Mixed lengths belong on the linear cut list. Mixed rectangles belong on the sheet page.