Kerf Compensation Calculator
Calculate the design offset for tight-fitting laser-cut joints and inlays. Enter your measured kerf width to get compensation values.
Your Measurements
The width of material removed by the laser cut
The size you want the slot or tab to be after cutting
Slots get smaller, tabs get larger
Results
Setting Kerf Offset in LightBurn
In LightBurn, select your cut layer and open the Cut Settings Editor. Enter the kerf offset value (0.100 mm) in the "Kerf offset" field. LightBurn will automatically shift the laser path inward for cuts and outward for outside contours.
Managing kerf settings across operators?
BeamFlow keeps job files, notes, and proof approvals in one place so nothing gets lost between jobs.
Start Your Free TrialHow to Measure Your Laser Kerf
Kerf varies by laser type, power, speed, material, and thickness. The only reliable way to get your kerf width is to measure it on your own machine with your own settings.
The 10-Square Method: Draw 10 identical squares (e.g., 10 mm x 10 mm) side by side with no gap between them. Cut them out. Push the 10 squares together tightly and measure the total width. Subtract that from the original design width (100 mm). Divide by the number of cuts (11 cuts for 10 squares). That is your kerf width.
Example: You design 10 squares at 10 mm each = 100 mm total design width. After cutting, you push the squares together and measure 97.8 mm. The difference is 2.2 mm across 11 cuts, so your kerf is 2.2 / 11 = 0.20 mm.
Typical ranges: CO2 lasers commonly produce a kerf between 0.07 mm and 0.50 mm depending on material and thickness. Thicker and denser materials tend toward wider kerf. Clear acrylic produces wider kerf than colored acrylic because the CO2 wavelength partially transmits through clear material before absorption. Fiber lasers cutting metal typically produce a narrower kerf (0.08 - 0.40 mm) due to their shorter wavelength and tighter spot size. Diode lasers tend to produce wider, less consistent kerf (0.15 - 0.50 mm) due to their rectangular beam profile.
Important: Always re-measure when you change materials, material thickness, or cut settings. Kerf can vary significantly even between different batches of the same material.
Typical Kerf Width Reference
These are approximate starting points. Always verify with a test cut on your machine.
| Material | Thickness | Laser Type | Typical Kerf |
|---|---|---|---|
| Acrylic (colored) | 1 mm | CO2 | ~0.07 mm |
| Acrylic (clear) | 3 mm | CO2 | ~0.10 - 0.20 mm |
| Acrylic | 5 - 8 mm | CO2 | ~0.17 - 0.20 mm |
| Plywood / MDF | 1.5 - 6 mm | CO2 | ~0.10 - 0.30 mm |
| Plywood / MDF | 6 - 12 mm | CO2 | ~0.20 - 0.40 mm |
| Leather | 1 - 4 mm | CO2 | ~0.10 - 0.30 mm |
| Mild Steel | 1 mm | Fiber | ~0.08 - 0.15 mm |
| Mild Steel | 3 - 6 mm | Fiber | ~0.15 - 0.35 mm |
| Aluminum | 1 - 3 mm | Fiber | ~0.10 - 0.30 mm |