Saw Kerf Explained: Why It Matters for Your Cut List

Saw kerf is the width of material removed by a saw blade during each cut — typically 2.5–3.5mm (3/32" to 1/8") for standard table saw blades. Failing to account for kerf in your cut list can result in undersized parts, wasted sheets, and inaccurate material estimates. It's one of the most commonly overlooked factors in manual cut list planning — and one of the first things a good optimizer handles automatically.

What Is Saw Kerf?

When a saw blade passes through a sheet of material, it doesn't just separate two pieces — it destroys a thin strip of material, converting it to sawdust. That strip is the kerf: the slot or channel left by the blade.

Kerf width is determined by two factors:

• Plate thickness: The body of the saw blade (usually 1.8–2.8mm)
• Tooth set: Saw teeth are bent or set slightly wider than the plate so they don't bind. The combined width is the actual kerf.

The material within the kerf is gone permanently — it becomes sawdust. This is distinct from scoring, snapping, or laser cutting, where different amounts of material are removed (or none at all).

Common Kerf Widths

How Kerf Affects Your Cut List

Let's work through a concrete example. You need to cut 8 pieces, each 300mm wide, from a single 2440mm-long sheet.

Without accounting for kerf:
8 × 300mm = 2400mm. The sheet is 2440mm, so you have 40mm to spare. Looks fine.

With a 3.2mm kerf (7 cuts between 8 pieces):
8 × 300mm + 7 × 3.2mm = 2400 + 22.4 = 2422.4mm. Still fits with 17.6mm spare.

With a 4.5mm kerf (industrial panel saw):
8 × 300mm + 7 × 4.5mm = 2400 + 31.5 = 2431.5mm. Still fits, but only 8.5mm spare — a very tight margin.

Now scale this up. A complex cabinet project might require 60+ cuts across multiple sheets. With a 3.2mm kerf, 60 cuts removes 192mm of material — nearly 8 inches. That's potentially a whole additional part lost to sawdust if you didn't plan for it.

The cut list optimizer factors kerf into every gap between adjacent parts on the layout. When you enter your kerf width, the optimizer reserves that space between every cut pair — so your printed part dimensions remain accurate and your sheet count is correct.

Setting Kerf in Your Optimizer

In CutPlan, kerf width is set in the project settings and applied globally to all cuts. Here's how to get it right:

Measure Your Actual Blade

Don't assume the default. Blade kerf varies by brand, age, and whether the blade has been re-tipped. To measure:

1. Make a cut through a scrap piece of MDF or plywood
2. Use digital vernier calipers to measure the width of the slot
3. Take three measurements at different points along the cut and average them
4. Enter the result in CutPlan's kerf field

Round Up Slightly

If your blade measures 3.0mm, enter 3.2mm. A slightly generous kerf setting wastes a tiny amount of sheet space between parts — that's acceptable. An underestimate causes parts to measure slightly too wide to fit their allocated space, which you only discover at the saw.

For CutPlan's kerf setting, you can enter values to one decimal place. A kerf of 3.2mm on a project with 40 cuts reserves 128mm — about 5 inches — which is the actual material your blade will remove.

Thin-Kerf vs. Standard Blades

Thin-kerf blades (2.4mm vs. 3.2mm) save approximately 25% of kerf waste. On a project with 50 cuts, that's the difference between removing 120mm and 160mm of material — about 40mm (1.5 inches) saved.

On a large project using expensive hardwood plywood, a thin-kerf blade can easily save one sheet per 20 sheets cut — often more than the cost of the blade itself. For budget sheet materials and occasional cutting, a standard blade is fine.

For more ways to reduce material loss beyond kerf management, see our guide on minimizing wood waste in panel cutting.

Frequently Asked Questions