Kerf Cut List Calculator
Every saw cut turns a blade-width of stock into sawdust, and on a long cut list that kerf adds up. Dividing board length by part length without allowing for kerf overstates how many parts you get and leaves you short. This calculator subtracts a kerf for each cut between parts, returns the maximum whole parts that fit on one board, and shows the stock length actually consumed including kerf. Add a trim allowance if you square the board ends first.
Kerf cut list formula
parts = floor((board length + kerf) / (part length + kerf))
stock used = parts * part length + (parts - 1) * kerf
Adding one kerf to the board length and dividing by part-plus-kerf accounts for n parts needing n minus 1 internal cuts. The stock used adds the part lengths plus the kerf lost between them.
Worked example
A 96 inch board cut into 12 inch parts with a 0.125 inch kerf: parts = floor((96 + 0.125) / (12 + 0.125)) = floor(96.125 / 12.125) = floor(7.93) = 7 parts. Stock used = 7 * 12 + 6 * 0.125 = 84 + 0.75 = 84.75 inches. Ignoring kerf would wrongly suggest 8 parts.
Kerf cut list: frequently asked questions
What is kerf?
Kerf is the width of material a saw blade removes with each cut, equal to the blade and set width. A typical table-saw blade has a kerf around 0.125 inch (one eighth of an inch), and thin-kerf blades around 0.094 inch. Every cut between parts turns one kerf width of stock into sawdust, so it must be accounted for in a cut list.
How many parts fit on a board with kerf?
Each part needs its own length plus one kerf for the cut that frees it from the rest of the board, except the layout can be arranged so the number of kerfs is one less than the number of parts. This calculator computes the maximum whole parts of a given length that fit in your board length once each internal cut loses a kerf.
Why does ignoring kerf cause shortages?
If you divide board length by part length without subtracting kerf, you overestimate yield. On a long board with many parts the lost kerf adds up to a full part or more, leaving you short. Including kerf gives an honest count and the true stock length you must buy.
Does the first or last cut count?
For n parts cut from a single board you make n minus 1 internal cuts between them (plus possibly trimming the ends). This calculator counts the internal kerfs between parts. Add an allowance for squaring the ends if your stock needs trimming before the first part.
Sources and method
- The yield formula is a standard packing calculation that subtracts blade kerf for each internal cut. It is arithmetic, not a sourced figure. Enter your blade's actual kerf width.
- National Institute of Standards and Technology: Office of Weights and Measures (length units).
Reviewed by the CalculatorHub team, edited by James Graham, 19 June 2026. See our methodology.