Board Cut Calculator
List the pieces you need and the board lengths you can buy, and see how to cut them from the fewest boards or for the least money, with the saw kerf and end trim counted.
Stock boards
| Label | Length (in) | Qty | Cost | Remove |
|---|---|---|---|---|
Leave Qty blank for unlimited boards.
Pieces
| Label | Length (in) | Qty | Remove |
|---|---|---|---|
Results
- Boards
- 6
- Pieces cut
- 14 of 14
- Waste
- 14.6%
- Material cost
- 27.00
- 6 boards of 2x4 stud (96 in) · 27.00
Kerf 1/8 in · End trim 0 in each end
Cutting diagrams
Cut list
| Piece | Length (in) | Qty | Board |
|---|---|---|---|
| Leg | 34 1/2 | 4 | 1, 2, 3, 4 |
| Long rail | 57 | 4 | 1, 2, 3, 4 |
| Short rail | 21 | 4 | 5 (×4) |
| Top support | 21 | 2 | 6 (×2) |
How to use it
- Add the boards. Enter each length you can buy, such as 8, 10 and 12 ft (96, 120 and 144 in.), leaving Qty blank for no limit, or the boards already on your rack with how many you have. Add the cost of each board if you want the cheapest mix.
- Add the pieces. Give each one a label, its length and how many you need. Fractions (30 1/4), decimals and feet and inches (2' 6") all work.
- Set kerf and end trim. Kerf is the width of the blade's cut. End trim is cut off each end of every board before any piece is measured.
- Read the plan. Each board is drawn to scale with its pieces in order from one end and the usable offcut left at the other, along with totals for boards, waste and cost. Print it, or keep it on your phone at the saw; the list is saved in this browser.
Kerf adds up faster than you think
Each cut turns a slice of wood as wide as the blade's kerf into sawdust. Pieces sit end to end with one kerf between neighbors, and the last piece can run right to the end of the board, so n pieces on one board need their total length plus (n − 1) kerfs.
Example: six 32 in. legs for a long workbench, from 8 ft boards. By length alone, 6 × 32 = 192 in., exactly two 96 in. boards. But three legs on one board need 3 × 32 + 2 × 1/8 = 96 1/4 in., so each 8 ft board yields only two legs and you need three boards. If your boards measure 96 1/4 in. or more and their ends are clean, two boards do work, which is why measuring your stock matters.
For example, Diablo publishes 0.098 in. for its D1050X and D1060X 10 in. blades, 0.118 in. for its 12 in. D1280X and 0.059 in. for its 7-1/4 in. circular saw blades. See the saw blade kerf guide for sources and how to measure your own.
End trim
Board ends are rarely ready to use. They can be split (end checks), out of square, stamped, painted or stapled, and boards you plane yourself can have snipe, a slightly thinner section near each end. Enter the amount you'll cut off each end, counting the blade's kerf, and the calculator removes it from both ends of every board before placing pieces. If you only square one end, enter that amount and treat it as a little extra margin at the other.
Buying common lumber lengths
Softwood lumber in the U.S. is graded under the American Softwood Lumber Standard (PS 20-25), which sets standard lengths in multiples of 1 ft or 2 ft, as each grading agency's rules specify. The same standard explains two things worth knowing before you plan:
- Actual length can exceed the label. Unless the sale says otherwise, lumber 2 in. or less in nominal thickness is trimmed at both ends to at least its nominal length and, for most sizes, no more than 3 in. over. An "8 ft" board should be at least 96 in. and may be a bit longer, but check: a split or damaged end still has to come off.
- Width and thickness are smaller than the name. A dry 2 × 4 is dressed to 1 1/2 × 3 1/2 in. and a 1 × 6 board to 3/4 × 5 1/2 in. This calculator works in lengths only, but the actual size matters when you work out the lengths of parts that butt into each other.
Precut studs, sold for standard wall heights, are shorter than their nominal wall height, so measure them before you count on a length.
Longer is not automatically cheaper. For the 32 in. legs above, with a 1/8 in. kerf: an 8 ft board holds two (31 3/4 in. left over), a 10 ft board holds three (23 5/8 in. left) and a 12 ft board holds four (15 1/2 in. left). Six legs take three 8 ft boards (24 ft of lumber), two 10 ft boards, or one 12 ft and one 8 ft (20 ft either way). Enter what each length costs at your yard and the calculator picks the cheapest combination; it is also worth asking whether the long boards fit in your vehicle.
Hardwood from a lumberyard often comes in mixed lengths and is priced by the board foot. Measure the boards you pick and enter each length as its own stock row with its quantity.
Width, defects and other limits
The board calculator plans lengths only. If parts need ripping to different widths, rip first and plan each width as its own list, or use the sheet optimizer for wide parts and glued-up panels. To work around knots, cracks or a bowed section, cut them out first and enter the clear lengths as separate boards.
Frequently asked questions
Can I get four 24 in. pieces from an 8 ft board?
Only if the board is at least 96 3/8 in. long. Three cuts with a 1/8 in. kerf remove 3/8 in., so from exactly 96 in. you get three 24 in. pieces and one at 23 5/8 in. Many boards are a little long: under the American Softwood Lumber Standard (PS 20-25), lumber 2 in. or less in nominal thickness is normally trimmed to at least its nominal length and no more than 3 in. over. Measure the boards you actually have and enter that length.
What kerf should I use for a miter saw?
Use your blade's spec or measure it. For example, Diablo lists 0.098 in. (2.5 mm) for its D1060X 10 in. 60-tooth blade and 0.118 in. (3.0 mm) for its D1280X 12 in. 80-tooth blade. The kerf guide has more blades and a quick way to measure.
Should I enter prices?
Enter them when you can buy more than one length. With a price on every board length the calculator looks for the cheapest mix; without prices it uses the least total board length. Price per board is what matters, so long boards that cost more per foot can lose to shorter ones.
In what order should I make the cuts?
Each board is listed from one end, longest piece first. Square the end if you set an end trim, then measure each piece from the freshly cut end and cut on the waste side of your mark, so the kerf comes out of the rest of the board and not out of the piece you just measured.
Does it work for trim, dowels, pipe or metal?
Yes. Anything you cut to length works the same way: baseboard and casing, closet rod, conduit, threaded rod, aluminum extrusion. Enter the kerf of the saw you'll use for that material.
Why is the waste percentage higher than the leftover pieces suggest?
Waste is measured against the full length of every board you buy, so it includes end trim and every kerf as well as the offcuts. On a job with many short pieces the kerfs alone can add up to several inches.
Is the result guaranteed to be the best?
No. The calculator compares several methods, including a search for the combination of pieces that fills each board best, and keeps the plan that costs least or uses the least lumber. It works board by board, so a better overall plan can still exist, and on large jobs the search stops after a fixed amount of work. See the methodology.