Kerf is the material your saw blade removes during each cut. Without accounting for kerf, every piece in your cut list will be slightly short — and the error compounds across multiple cuts.
Standard Kerf Widths
| Blade type | Kerf width | Decimal |
|---|---|---|
| Standard table saw | 1/8″ | 0.125″ |
| Thin-kerf table saw | 3/32″ | 0.094″ |
| Standard circular saw | 1/8″ | 0.125″ |
| Japanese pull saw | 1/32″ | 0.031″ |
| Band saw (1/4″ blade) | 1/16″ | 0.063″ |
The Formula
Total material needed = sum of all cut lengths + (number of cuts − 1) × kerf width.
Example: cutting 3 pieces of 11 1/4″ each with a 1/8″ kerf blade requires 33 3/4″ + 2 × 1/8″ = 34″ of board.
Using TapeMath’s Cut List Builder
Switch to the Cut List tab, enter each piece length, select your kerf from the pill buttons (1/8″ or 1/16″, or type a custom width), and TapeMath calculates the total automatically including all kerfs.
Key rule: You need one kerf for every cut — which is one fewer than the number of pieces. Three pieces = two saw cuts = two kerfs.