Saw kerf in a cut list

Kerf is the width of material actually removed by the cut. Every separating cut consumes that width, so ignoring it can make a layout physically impossible.

Measure the result, not the label

Make a representative test cut using the blade, machine and settings intended for the job. Measure the material removed or compare the two remaining pieces with the original width.

Do not confuse kerf and trim

Kerf lies between parts. Trim reserves an unusable border around a sheet for squaring, damage or a clean factory edge. They solve different problems and both may apply.

Use a realistic margin

A deliberately tiny kerf may squeeze one more part onto the drawing while making the plan impossible at the saw. Use the repeatable workshop result, not the most convenient number.

Questions

Is kerf the thickness of the blade plate?

Not necessarily. Tooth set, run-out and cutting conditions can make the actual cut wider than the plate.

Does a CNC router use kerf?

For nesting, router-bit clearance and part spacing play a similar geometric role, but toolpaths and holding requirements are separate decisions.

What happens if I change kerf?

Part positions and sometimes the number of sheets can change, especially where rows are tightly packed.