Saw Blade Kerf Explained

Saw blade kerf is the width of material the blade removes on each cut, and it is the main reason a tight cut list comes out short. If you have ever cut a stack of shelves from a sheet of plywood and ended up with the last shelf 5 mm too narrow, you have already met kerf in person. This guide covers typical kerf widths, how kerf changes sheet yield, and how to account for it in your cut list.

What is saw blade kerf?

A saw blade is not infinitely thin. The teeth are wider than the body of the blade so it does not bind in the cut, and that width is what the blade grinds away as it passes through the wood. That gap left behind is the kerf. On a typical panel saw the kerf is about 3 mm; on a fine track-saw blade it can be as little as 2.2 mm; on a 6 mm CNC router bit it is a full 6 mm.

The important thing to understand is that every cut takes away kerf from something. If you draw two 600 mm shelves side by side on a sheet and cut between them, one of them ends up 597 mm, or both end up 598.5 mm, depending on where your mark was. Multiply that across a full cutting list and by the time you get to the last part on the sheet you can be 15–20 mm short.

Typical kerf widths

The table above shows typical values. Your real kerf depends on the blade, tooth set, sharpness and arbor play, so measure your own blade before you trust a number. A wider overview by tool type:

• Industrial vertical panel saw: 3.2 – 4.4 mm
• Sliding table saw: 3.0 – 3.5 mm
• Beam saw / CNC panel saw: 3.8 – 4.8 mm
• Track saw: 2.2 – 2.5 mm
• Cabinet table saw, full-kerf blade: 3.0 – 3.2 mm
• Cabinet table saw, thin-kerf blade: 2.0 – 2.4 mm
• Contractor / job-site table saw: 2.4 – 3.0 mm
• Compound mitre saw: 2.0 – 3.0 mm
• Circular saw with rip blade: 1.8 – 2.5 mm
• Jigsaw (T-shank wood blade): 1.0 – 1.8 mm
• Band saw (¼" to ½" blade): 0.8 – 1.2 mm
• Scroll saw: 0.4 – 0.8 mm
• CNC router, 6 mm compression bit: 6 mm
• CNC router, 3 mm bit: 3 mm
• Laser cutter (plywood, 3–6 mm): 0.1 – 0.3 mm

These are ranges, not gospel. The exact number depends on the specific blade, its tooth geometry, whether it is new or dull, and how much side play the arbor has. If accuracy matters, measure your own — see below.

Measure your own kerf in 60 seconds:

1. Take a piece of scrap at least 200 mm long.
2. Measure it with callipers and write down the length.
3. Make a single cut roughly in the middle. Do not move the piece.
4. Measure the two halves and add them together.
5. The difference between the original length and the sum of the halves is your kerf.

Example: 200.0 mm scrap, cut in half, halves measure 99.4 mm and 97.8 mm. Total 197.2 mm. Kerf = 200.0 − 197.2 = 2.8 mm. That is the number to type into the optimizer.

How kerf changes sheet yield

A cutting-list optimizer like OptimalLayout does not just pack rectangles — it packs rectangles with a gap between them. That gap is your kerf. Set the kerf too small and the optimizer will fit an extra part on the sheet that will not actually fit once you cut. Set it too big and the optimizer wastes a strip you could have used.

On a full 2440 × 1220 mm sheet, changing the kerf from 2 mm to 4 mm typically costs you one usable strip of material — often the difference between fitting all your parts on one sheet and needing a second. Getting the number right is worth a few minutes.

Examples per saw type.

Track saw, measured 2.2 mm. You break down a 2440 × 1220 mm melamine-faced chipboard sheet and a fresh 48-tooth blade. Measured kerf: 2.2 mm. For the 608 mm cabinet sides in the worked example below, four parts fit end to end in every strip: 4 × 608 + 3 × 2.2 = 2438.2 mm, just under the 2440 mm sheet length. That fourth part per strip is free material.

Table saw, full-kerf blade, 3.2 mm. The same parts on a cabinet table saw with a standard 60-tooth ATB blade: 4 × 608 + 3 × 3.2 = 2441.6 mm — 1.6 mm over. Only three parts fit per strip, and the whole sheet drops from 12 to 9 parts. Nothing else changed: same sheet, same parts, only the kerf field in the cut list.

Sliding table saw, 4.0 mm. A joinery shop ripping melamine on a sliding table saw with a scoring blade measures 4.0 mm. The extra width does not change the three-per-strip count on the 608 mm part, but on tighter layouts — parts 610 or 612 mm long — it is the difference between a row fitting or not. The payoff is tear-out-free edges on melamine, worth more in saved touch-up sanding than the kerf costs.

CNC router, 6 mm bit. A 6 mm compression bit removes a full 6 mm on every pass. On the same 608 mm part: 4 × 608 + 3 × 6 = 2450 mm — no fourth part, and the nesting software has to compensate the toolpath outward. That is why kerf on a CNC equals the bit diameter: you cannot optimize it away, you plan around it.

Worked example: what kerf really costs.

Take a real job: 40 cabinet side panels of 608 × 400 mm, cut from 18 mm birch ply, on 2440 × 1220 mm sheets at €55 each. The sheet is 1220 mm wide, so three rows of 400 mm parts fit across the width (3 × 400 + 2 × 3.2 = 1206.4 mm). The question is how many 608 mm parts fit along the 2440 mm length of each row.

At 3.2 mm kerf: 4 × 608 + 3 × 3.2 = 2441.6 mm — too long, so each row yields 3 parts and one sheet holds 3 × 3 = 9 parts. At 2.2 mm kerf: 4 × 608 + 3 × 2.2 = 2438.2 mm — it fits, so each row yields 4 parts and a sheet holds 12. For 40 panels that is 5 sheets versus 4: one whole sheet saved, about €55, by a one-millimetre difference in a single number.

You can also express it as area. Nine parts cover 9 × 0.243 m² = 2.19 m² of a 2.98 m² sheet — roughly 27% ends up as offcuts and sawdust. Twelve parts cover 2.92 m², leaving under 2% waste. Same job, same sheet, only the kerf entry changed.

Note what did not change: the parts, the sheet size and the material. The only variable was the kerf field. That is why measuring your own blade — 60 seconds, a scrap piece and callipers — pays for itself the first time a layout tips from 5 sheets to 4. If your real kerf sits between the two, enter the larger value for parts that must fit exactly, and let the optimizer show you both scenarios before you buy material.

We ship with a 3 mm default because it matches the panel saws and full-kerf table saws that most working cabinet shops use, and it is safe: if your real kerf is smaller, you get a little extra yield; if your real kerf is larger you have not overcommitted the sheet.

If you know you use a track saw or a thin-kerf blade, drop it to 2.4 mm and you will typically squeeze one or two extra small parts per sheet. If you cut on a CNC router, set the kerf equal to the bit diameter.

How to subtract kerf in a cut list

Example. You need three parts from one 2440 mm length: 600 + 400 + 720 mm = 1720 mm. Between them sit two kerf gaps of 3 mm = 6 mm. Total used: 1720 + 6 = 1726 mm on a 2440 mm sheet, leaving 714 mm before any trim cut.

The finished sizes of your parts stay the same — you never shrink a part to make room. Kerf sits between the cuts, so you subtract it from the material that is left, not from the parts themselves.

Warning: do not subtract kerf twice. If you use a sheet cutting calculator that already accounts for kerf, enter your true part sizes and let the tool add the gaps. Taking kerf off the parts as well makes every part too small. Try it in our free sheet cutting calculator.

• Forgetting the first cut. The very first cut on a fresh sheet also removes kerf. OptimalLayout accounts for this automatically — you can measure straight from the diagram — but if you are drawing your own layout on paper, subtract kerf from the sheet edge too.
• Cutting all one direction first. If you rip a sheet into strips and then crosscut, the kerf on the rip cuts subtracts from the length of every part in that strip. Optimizers assume this; hand-drawn layouts often do not.
• Mixing blade types on one project. If you break down a sheet with a track saw and then finish on the table saw, use the larger of the two kerfs when planning, or split the layout into two stages.
• Assuming the blade has not dulled. A dull blade wobbles, and a wobbling blade cuts a wider kerf. If you have not changed the blade in six months, measure again.

Kerf on plywood, MDF and melamine

Kerf itself does not change much between materials — it is set by the blade — but how clean that kerf is does. Plywood splinters on the exit side, MDF cuts cleanly but produces fine dust, and melamine chips easily along the face. A scoring blade, a zero-clearance insert or tape on the cut line helps you reduce tear-out; a scoring blade can also add a fraction of a millimetre to the effective kerf, so measure with it fitted.

Kerf is not just an accuracy issue — it is a materials cost. On a €80 sheet of 18 mm birch ply, one wasted strip is €8 in the bin. Across a kitchen with six sheets, getting the kerf right can be €30–€50 back in your pocket. That is why we treat the kerf field as the single most important input in the optimizer after the sheet size itself.

Measure your kerf once, write it on a piece of tape stuck to your saw, and use that number every time you plan a cut list. If you are not sure, start with 3 mm — it is a safe default that will not leave you with parts too small to use.

Next steps. Head over to the optimizer and enter your real kerf value, or read our guide on cutting optimization to see why the algorithm cares so much about that one number.

FAQ

What is a normal saw blade kerf?

A standard full-kerf blade removes about 3.2 mm (1/8 in), while thin-kerf and many track saw blades sit around 1.6 – 2.2 mm. Always measure your own blade, because sharpness and tooth set change the real number.

Do I add or subtract kerf?

Keep your part sizes as they are and add one kerf width for every cut between parts when you check whether they fit on the sheet. If your calculator already handles kerf, enter only the finished part sizes.

Is a thin-kerf blade always better?

A thin-kerf blade wastes less material and needs less power, which can fit an extra part on a sheet. It can also flex or wander more on thick or dense panels, so a full-kerf blade is often more accurate for heavy cuts.