Cut list optimizer

How to plan your cuts

1. Choose Sheets for plywood, MDF or melamine, or Boards for 2x4s, studs, trim or pipe, and the unit. Inches take fractions: 23 5/8.
2. List the parts with a name, the length and width (finished sizes) and how many. Tick grain on parts whose grain must run along their length, such as cabinet sides and visible shelves. Or paste the list from a spreadsheet.
3. Enter your stock: the sheet size or board lengths you have or will buy, and how many. Then set your blade's kerf and, for sheets, an edge trim if the factory edges are rough.
4. Read the diagram. Parts that fit no sheet, or for which the stock ran out, are named in red above it. Check the offcuts: a big one may hold another part if you add it.
5. Print the PDF and cut in the numbered order: on a sheet, the rips (cuts along its length) first, then the crosscuts, then the short cuts that free stacked parts.

What it cannot do

• Guillotine layouts only. Every cut runs edge to edge across the piece, so there is no nesting of curved or irregular parts for a CNC router, and no L-shaped or notched parts. Enter those as the rectangle they are cut from.
• Not a proven optimum. Packing is a hard problem, so the layout is the best this page found, not a proven optimum. It tries several orders and orientations and keeps the fullest sheet each time; on some lists a person can still save a sheet by hand.
• No edge banding, hardware or cost lists. It works out cuts and nothing else: no banding lengths, no screws or hinges, no prices.
• One thickness per job. Mixed 12 mm and 18 mm parts are two jobs (or two saved PDFs); it does not know which part is which material.
• Up to 1,500 parts in one job and 200 rows in a list. The PDF draws every label, but on a crowded sheet the smallest labels are tiny; the list under each diagram names every part as well.

How the layout is made

Sheets. The sheet's first dimension is its length; the grain runs along it. Rips along the length split the sheet into strips, as wide as the first part placed in each; crosscuts split each strip into pieces; parts that are narrower than the strip are stacked in a piece and freed with a short rip, and a last crosscut trims a part to length. Each cut takes one kerf of material. The page tries four orders (widest first, largest area, longest first, largest side) with parts turned two ways, keeps the run that fills the sheet best, and moves on to the next sheet. With several stock sizes it picks, for each sheet, the size that it can fill best.

Boards. Parts are packed longest first into the first board with room (first-fit decreasing); then a second pass empties the least-full boards into the others' leftovers where it can, and swaps any board for a shorter stock length that still holds its parts.

Waste is everything that is not a part: offcuts, saw kerf, edge trim and slivers. Offcuts are listed with their sizes because many are worth keeping. Example with kerf 3.2 mm: four 600 mm parts across a 2440 mm sheet use 4 × 600 + 3 × 3.2 = 2409.6 mm, so they fit with a 30.4 mm strip left before the last cut; four 610 mm parts need 2449.6 mm and do not fit, so the fourth goes to another sheet.

Real sizes. A European sheet is usually 2440 × 1220 mm (some MDF and melamine 2800 × 2070 or 2500 × 1250); a North American 4 × 8 sheet is 48 × 96 in, 1219.2 × 2438.4 mm, and is what the 8 × 4 ft preset gives. A 2x4 is planed to 1 1/2 × 3 1/2 in; in Boards mode only its length matters.

Questions

Is this cut list optimizer free, or do I need to download an app?

It is free and it is this web page: no download, no account, no limit on sheets or parts and no watermark on the PDF. It runs in the browser on a phone, tablet or computer, and your cut list stays on that device.

Can it work out cuts for 2x4s and other lumber?

Yes. Switch to Boards (linear) and enter your stock lengths, for example 8 ft, 10 ft and 12 ft 2x4s, and the lengths you need with their quantities. Only the length matters in this mode, so it works for studs, trim, dowel, pipe, aluminium extrusion or anything else you cut to length. Each board is drawn with its parts, the saw cuts and the leftover.

How does the linear cut list optimizer decide which board each piece comes from?

It sorts the parts longest first and puts each into the first board that still has room, counting one saw kerf between parts (first-fit decreasing). Then an improvement pass tries to empty the least-full boards into the leftovers of the others, and swaps any board for the shortest stock length that still holds its parts. Three 800 mm parts on a 2438 mm board need 2400 mm plus two 3 mm kerfs, 2406 mm, so they fit with 29 mm left after the last cut.

How does it lay out cuts on a sheet of plywood?

As a guillotine layout: rips along the length of the sheet split it into strips, crosscuts split each strip into pieces, and short cuts free parts stacked in one piece. Every cut runs from one edge of the piece being cut to the other, so the diagram can be cut on a table saw, panel saw or track saw without plunge cuts. The cuts are numbered on the diagram in that order. A part with the grain lock on keeps its length along the sheet's length; the others may be turned 90 degrees.

How much should I allow for the saw kerf?

Use your own blade's kerf: cut into a scrap and measure the slot. A full-kerf table saw blade is about 3.2 mm (1/8 in) and a thin-kerf blade about 2.4 mm (3/32 in); that is why the default is 3.2 mm. It adds up: four 600 mm parts across a 2440 mm sheet need 2400 mm plus three kerfs, 2409.6 mm, and fit, but four 610 mm parts need 2449.6 mm and do not.