Count the strips a board will give before you start ripping. Every cut eats a kerf, and every strip you joint loses a little more. Enter the board, the strip, and the blade; get the count, the leftover, and the width you would need for more.
Use this when ripping edging, slats, lattice, bent-lamination strips, or face-frame stock from wide boards, and you want to know whether one board is enough or you need two.
Measure the actual board width. Enter the kerf of the blade you will use (measure a test cut — thin-kerf and full-kerf blades differ), the trim needed to give a straight first edge, and any cleanup you will take off each strip on the jointer or planer.
The count assumes all strips are the same width and ripped one after another from the same board.
The first strip comes off the straightened edge. Every strip after that costs one more kerf, but there is no kerf after the last strip — the leftover offcut is whatever remains. That is why the formula adds one kerf to the usable width before dividing by strip plus kerf.
If each strip needs a jointer pass to clean the sawn edge, rip it that much oversize; the cleanup allowance is added to every strip. The optional target count runs the same arithmetic backwards to give the board width you need.
usable = board − first-edge trim
strips = floor( (usable + kerf) / (strip + cleanup + kerf) )
leftover = usable − strips × (strip + cleanup) − (strips − 1) × kerf
width for N strips = N × (strip + cleanup) + (N − 1) × kerf + trim
Each row below starts from the default inputs and changes only the columns shown. Recompute any row by hand with the formula above.
| Board | Strip | Kerf | Trim | Cleanup | Strips | Leftover |
|---|---|---|---|---|---|---|
| 7.25 | 1.5 | 0.125 | 0.125 | 0 | 4 | 0.750 |
| 7.25 | 1.5 | 0.094 | 0.125 | 0 | 4 | 0.843 |
| 7.25 | 1.5 | 0.125 | 0.125 | 0.0625 | 4 | 0.500 |
| 5.5 | 0.75 | 0.125 | 0.125 | 0 | 6 | 0.250 |
| 11.25 | 2 | 0.125 | 0 | 0 | 5 | 0.750 |
| 3.5 | 0.125 | 0.094 | 0 | 0 | 16 | 0.090 |
With the calculator defaults (Board width (in) = 7.25; Finished strip width (in) = 1.5; Saw kerf (in) = 0.125; First-edge trim (in) = 0.125; Cleanup per strip (in) = 0; Target strips (optional) = 0), the arithmetic runs like this:
usable = board − trim = 7.25 − 0.125 = 7.125 in
strips = floor((usable + kerf) / (strip + cleanup + kerf)) = floor(7.25 / 1.625) = floor(4.4615) = 4
leftover = usable − n × (strip + cleanup) − (n − 1) × kerf = 0.7500 in
Result: 4 strips. Each strip 1.5 in, 0.125 in kerf. Leftover offcut 0.750 in (3/4 in).
Now change Target strips (optional) to 5 and leave everything else alone:
usable = board − trim = 7.25 − 0.125 = 7.125 in
strips = floor((usable + kerf) / (strip + cleanup + kerf)) = floor(7.25 / 1.625) = floor(4.4615) = 4
leftover = usable − n × (strip + cleanup) − (n − 1) × kerf = 0.7500 in
width for 5 strips = N × (strip + cleanup) + (N − 1) × kerf + trim = 8.1250 in
Result: 4 strips. Each strip 1.5 in, 0.125 in kerf. Leftover offcut 0.750 in (3/4 in). 5 strips need a 8.125 in board.
Four strips fit with 0.75 in to spare, but five need an 8.125 in board — 7/8 in more than a 1×8 offers, so a 1×10 or a second board is the honest answer.
Measure kerf by making a short cut in scrap and reading the slot with calipers. Blade wobble and a resharpened set can make the real kerf wider than the box says, and over ten rips that difference becomes a lost strip.
Re-joint the board edge between rips if the strips need a clean edge on both sides, and enter that jointer pass as the cleanup allowance.
For thin strips (bent laminations, lattice), a thin-rip jig that puts the strip on the outside of the blade keeps the strip from being trapped between blade and fence. The yield arithmetic is the same.
Units: Inches throughout. The leftover is also shown to the nearest 1/16 in.
Where the model stops: Equal-width strips from one board, straight-line ripping. Knots, checks, and defects you have to cut around are not modeled.
Not a substitute: Use a riving knife, a push stick, and a proper thin-rip setup for narrow strips. This page is quantity math only.
There are n strips but only n − 1 cuts between them. Adding one kerf to the usable width and dividing by strip-plus-kerf counts that correctly.
Only if it is at least as wide as a strip, in which case the count would already include it. The leftover shown is always narrower than one strip plus its cleanup.
No — set it to 0. Use it when you need a pass to straighten a crooked or waney edge.
This page only handles width. For cross-cuts, the same idea applies along the length with the miter saw kerf.