Rip Cut Calculator

How the Calculator Works

The Rip Cut Calculator answers a simple but critical woodworking question: how many strips of a given width can I actually get out of this board once I account for the blade? It uses the formula N equals the floor of (board width plus kerf) divided by (rip width plus kerf). This works because every cut after the first one removes a kerf's worth of material, so the total space consumed by N strips and the N minus one cuts between them must stay within the board's width. The calculator also reports how much material the cuts wasted, how much usable board is left over as a skinny final strip, and the overall efficiency of your layout as a percentage.

Understanding Kerf

Kerf refers to the slot of material removed by the saw blade as it passes through the wood. It is equal to the width of the teeth, not the body of the blade, because the teeth are set slightly wider to keep the body from binding in the cut. Table saw blades typically have a kerf between 0.094 inches for thin-kerf blades and 0.156 inches for heavy-duty full-kerf blades. Track saws and circular saws fall in the same range. Bandsaws have the smallest kerfs, often as narrow as 0.025 inches. Hand saws, rip handsaws, and Japanese pull saws vary widely and should be measured directly.

Choosing the Right Blade Kerf

Thin-kerf blades waste less wood and place less load on an underpowered saw, which makes them a good match for contractor saws and jobsite saws with motors under 2 horsepower. The downside is that the thinner plate flexes more easily, so cut quality can suffer in hardwoods if the blade is not stabilized with a stiffener. Full-kerf blades stay flatter through dense material, produce cleaner rip cuts, and last longer between sharpenings, but they need a cabinet saw with a stout motor to avoid bogging down. Choose the blade that matches your saw and your species, then dial the kerf into this calculator to plan accurately.

Planning Efficient Cut Lists

When you are ripping expensive hardwood, efficiency matters. Use the calculator to test different strip widths against your available board and see which combination produces the least waste. Sometimes a tiny adjustment, such as dropping your finished strip width from 2.5 inches to 2.4375 inches, lets you squeeze in an extra strip per board and can save hundreds of dollars across a large project. It is also smart to lay out the widest pieces first and let the narrow strips come from the leftover, because wide pieces are harder to source from the offcuts later.

Frequently Asked Questions

What is a saw kerf?

A saw kerf is the width of material the blade removes with each cut. For a table saw, typical kerfs are 0.094 inches for a thin-kerf blade and 0.125 inches for a standard full-kerf blade.

How do I measure my blade's kerf?

Check the manufacturer specs printed on the blade or measure it directly with digital calipers across two adjacent carbide teeth at their widest point.

Does a thinner kerf save much wood?

On a single cut the savings are small, but across many rips the difference can add up to a full extra strip per board on wide stock.

Why account for kerf when planning rips?

Ignoring kerf makes your cut list run short. The kerfs between strips add up and leave the last strip undersized unless you subtract them in advance.

Can I use this for crosscuts?

Yes. The math applies to any series of parallel cuts. Just enter your board length and desired piece length instead of widths.