HomeKerf test and calculator
Kerf test pattern and fit calculator
Kerf is the width the beam removes. This page cuts a comb of notches around your material thickness and calculates kerf from a measured coupon. The notch that fits a scrap of the same sheet is the kerf to type into the box generator.
Exports SVG. See also Finger-joint box, Living hinge, Material test grid.
9 notches from 2.8 mm to 3.2 mm.
Sheet 140.8 × 34.4 mm.
Find the tightest notch a scrap of this material slides into. That offset is your kerf.
Red paths cut. Blue paths score. Black paths engrave. Import at 100% scale.
How to use it
- Enter the thickness you measured, not the number on the vendor’s listing.
- Keep the default offsets, from −0.20 mm to +0.20 mm, unless you already know the beam is wider.
- Cut the file. Slide a scrap of the same sheet into the notches. The tight one is your kerf.
- Or cut the square coupon, measure it, and use the calculator. An outside square comes out smaller by the kerf.
- Put that kerf into the finger-joint box before you cut the real job.
Related tools
Questions
What does a negative notch mean?
The notch is drawn narrower than the thickness. After the beam widens it, a −0.10 mm notch finishes near the real thickness when your kerf is about 0.10 mm.
Outside measurement or inside?
A part measured across its outside is smaller than drawn, so kerf = drawn − measured. A hole is larger, so kerf = measured − drawn.
Should I retest when I change speed?
Yes. Power, speed, focus, and the lens all change kerf. Retest when any of those change, and when you open a new sheet.