How to Account for Saw Kerf
Kerf is the material removed by the blade or cutting wheel. A cut list that ignores kerf can look correct on paper and still fail at the saw because finished parts plus cut loss exceed the stock size.
The rule to use before optimizing
Add kerf between separate finished parts, not inside the finished part dimension. If two parts are placed side by side, the optimizer must reserve one blade-width gap between them. In linear stock, every cut between pieces consumes one kerf length.
- Enter finished part dimensions as the size you need after cutting.
- Enter kerf as the real blade or wheel width.
- For exact-fit designs, leave a small practical margin for squareness, cleanup, and measurement error.
Worked example: two 24 inch panels on a 48 inch sheet
Two 24 in finished panels total exactly 48 in before cutting. With a 1/8 in blade cut between them, the raw width needed is 24 + 0.125 + 24 = 48.125 in, so the pair does not fit across a 48 in sheet.
| Item | Width |
|---|---|
| Panel A | 24 in |
| Kerf between panels | 0.125 in |
| Panel B | 24 in |
| Raw width required | 48.125 in |
When to override the calculator
Use the calculator as a planning aid, then verify the first cut on real stock. If a factory edge must be trimmed, if a cut will be cleaned up on a jointer, or if the saw leaves a rough edge, add that extra allowance separately.
Related StockCut tools
Quick FAQ
Should kerf be added to every part size?
No. Keep finished part dimensions unchanged and add kerf between separate cuts.
Why does a 24 + 24 layout fail on a 48 inch sheet?
The middle cut removes material, so the total raw width is finished part A + kerf + finished part B.
Can I use 1/8 inch as a default?
It is a common planning value, but the correct kerf is the measured width of your blade or cutting wheel.
Use the live calculator on this site to test the same assumptions with your own stock size, part list, kerf, strategy, and export needs.