Kerf Width Calculator
The Cut Itself Eats Material Too
Every cutting process — saw, plasma, laser, or torch — removes a strip of material as it separates two pieces, and that strip is the kerf. Ignore it when planning how many parts fit on a length of stock and the math looks fine on paper but comes up short on the shop floor, because each cut quietly consumes material that never becomes part of a finished piece.
The Formula
Parts = floor((Stock Length + Kerf) / (Part Length + Kerf))
Total Kerf Loss = Parts × Kerf Width
Material Used = (Parts × Part Length) + Kerf Loss
Total Kerf Loss = Parts × Kerf Width
Material Used = (Parts × Part Length) + Kerf Loss
Worked Examples
| Stock Length | Part Length | Kerf Width | Parts (with kerf) | Parts (ignoring kerf) | Remaining Stock |
|---|---|---|---|---|---|
| 96 | 10 | 0.125 | 9 | 9 | 4.875 |
| 120 | 15 | 0.09 | 7 | 8 | 14.37 |
The second row shows kerf actually costing a whole part — ignoring it predicts 8 parts fit, but accounting for the material lost to each cut, only 7 actually do.
Where This Calculation Matters
- Cut planning and nesting — determining exactly how many parts a length of stock will yield before committing material to a job.
- Material yield and waste tracking — quantifying how much of a cut's raw material is lost to the cutting process itself versus the finished parts.
- Process comparison — comparing yield between cutting methods with different kerf widths, such as a narrow-kerf band saw versus a wider plasma or oxy-fuel cut.
How to Use This Calculator
- Enter Stock Length — the length of raw material available.
- Enter Part Length — the finished length needed per part.
- Enter Kerf Width — the material lost per cut for your cutting process.
- Select Calculate to get the number of parts obtainable, kerf loss, and remaining stock.
Related Calculations
Once parts are cut to length, calculate their weight with the Metal Weight Per Foot Calculator.