How Much Is a Typical Laser Cutting Kerf?

Typical laser cutting kerf measures between 0.08 mm and 1 mm, with the exact value driven by laser source, material, thickness, and machine setup.

Fiber laser cutting usually produces a tighter kerf in the 0.15–0.5 mm band, while CO2 laser cutting tends to land in the 0.25–0.5 mm band — and both ends of those ranges shift upward as material thickness increases.

There are 4 practical reference points you can use when planning a job:

Fiber laser, thin sheet (0.5–3 mm steel or stainless): kerf typically 0.10–0.25 mm. Narrow beam focus and high power density keep the cut zone small.

Fiber laser, medium plate (4–12 mm carbon steel): kerf typically 0.25–0.50 mm. Thicker stock requires more dwell time per pass, which widens the cut.

CO2 laser, thin to medium sheet (1–6 mm steel): kerf typically 0.25–0.40 mm. The 10.6 µm CO2 wavelength produces a wider focused spot than fiber’s 1.06 µm.

High-power fiber on thick plate (15–25 mm steel, 6–12 kW): kerf typically 0.6–1.0 mm. Aluminium runs slightly wider at the same thickness because of its higher thermal conductivity.

Material chemistry shifts the numbers further.

Highly reflective alloys such as copper, brass, and some aluminium grades absorb fiber wavelengths less efficiently, which can widen the cut zone if power and speed aren’t matched.

Stainless steel cut with nitrogen usually gives you the cleanest, narrowest kerf because nitrogen is inert and prevents oxidation at the cut edge.

Mild steel cut with oxygen produces a slightly wider kerf but cuts faster on thick plate, since the exothermic oxygen reaction adds energy to the process.

For most production work, plan around a kerf compensation value of 0.1–0.2 mm per side on fiber-cut sheet metal, then validate that figure with a first-article measurement before releasing the full batch.