A free cutting length optimizer is a browser tool that takes one stock length, one kerf allowance, and a labelled cut list, then arranges the requested pieces into stock bars using a deterministic First Fit Decreasing heuristic. It expands every quantity into individual pieces, sorts them from longest to shortest, and places each into the first opened stock where it fits. If no existing stock can accept the next piece, a new one is opened. The output lists every stock piece, its assigned parts, consumed length, and leftover waste, along with totals for kerf, used material, and unused remainder. Because the sort and tie-breaking are stable, identical input rows in the same order always produce the same layout, which makes the plan easy to verify. The Cut List Optimizer handles rods, boards, pipes, rails, trim, and rolls that share one stock length, with kerf and waste shown explicitly so the math is visible.
What a Free Cutting Length Optimizer Actually Does
A free cutting length optimizer solves a bounded version of the one-dimensional cutting-stock problem: assigning requested shorter pieces to standard-length stock while reducing unused material. A Lehigh University engineering analysis of the cutting-stock problem frames it that way, defining the task as the assignment of shorter pieces to standard-length stock with the goal of reducing unused material (see the technical paper at engineering.lehigh.edu). In a workshop, that translates into a practical question such as "how many 8-foot 2x4s do I need to rip these fifteen parts?" with kerf and waste visible in the answer.
The Cut List Optimizer distinguishes itself from spreadsheet formulas and paid software in three concrete ways:
- No signup, install, or upload. The calculation runs in the browser, so a cut list and the resulting plan stay on the device.
- Deterministic output. Identical rows in the same order produce the same layout, which is useful when a shop needs to reproduce or audit a plan.
- Explicit kerf accounting. The kerf you enter is added once per requested piece, so the totals match the convention of a bandsaw, miter saw, or pipe cutter instead of being silently absorbed.
The tool is not a replacement for a shop drawing, a CNC controller, or a structural spec. It is a planning draft that brings kerf and waste out from hidden arithmetic and puts them next to the part assignments, line by line.
The Cut List Optimizer's Input Contract
The Cut List Optimizer accepts three things and only three things: a stock length, a kerf value, and one row per part in label, length, quantity format. Every value, including stock length and kerf, must use the same unit because the calculator does not convert. Quantities are whole numbers, the expanded piece list is capped at 1,000 to keep the browser responsive, and each part plus its kerf must fit inside one stock piece. Labels cannot contain commas because commas separate the three row fields.
| Field | Format | Example | Note |
|---|---|---|---|
| Stock length | number, single unit | 96 in | shared by every opened stock |
| Kerf | number, same unit | 0.125 in | added once per requested piece |
| Label | text, no commas | Top rail | used to identify each row in the plan |
| Length | number, same unit | 18.5 | must fit one stock after kerf |
| Quantity | whole number | 3 | expanded list capped at 1,000 pieces |
Run a Free Cutting Length Optimizer: Three Steps
Follow these three steps to build a cut plan with the Cut List Optimizer.
- Enter one stock length and the kerf consumed for each requested piece. For example, stock = 96 inches, kerf = 0.125 inches (a typical 1/8-inch blade). The kerf value is added once for every requested piece, so it matters.
- Add one row per part as label, length, quantity using a consistent unit. If stock is in inches, every length and every quantity must also be in inches, and quantities must be whole numbers. Example rows: Top rail, 18.5, 3 and Bottom rail, 18.5, 3 and Post, 22, 4.
- Build the heuristic plan, verify every assignment and shop allowance, then copy the stock-by-stock list. The result lists each stock piece with its assigned parts, consumed length, and remaining waste, plus totals for waste, kerf, and part utilization. Read it line by line before sending the file to the saw.
How Kerf and Waste Are Counted
The Cut List Optimizer uses a conservative, visible convention: every requested piece consumes its entered length plus one kerf. Two 4-unit pieces with a 1-unit kerf therefore consume 10 units of stock, not 8. The convention is shown in the totals so it cannot be hidden by accident.
Some real workflows can skip the final kerf when a stock end is accepted as a finished edge, while angled cuts, blade drift, or cleanup passes can consume more than one kerf. Adjust the value you enter so it matches the shop process instead of assuming the page knows the machine. For angled cuts or cleanup allowances, increase the kerf until the resulting totals match what the saw actually removes.
A worked example makes the accounting visible. Take a 10-unit stock, a 1-unit kerf, and three requests: two pieces of 4 units and one piece of 3 units. After sorting descending, the order is 4, 4, 3. Place the first 4 into Stock 1 (remaining 10 − 4 − 1 = 5). Place the second 4 into the same Stock 1 (remaining 5 − 4 − 1 = 0). Stock 1 is full at 10 consumed, parts 8, kerf 2, waste 0. Open Stock 2 and place the 3 (remaining 10 − 3 − 1 = 6). Stock 2 holds 1 piece of 3, parts 3, kerf 1, waste 6. Totals across both stocks: parts = 11, kerf = 3, waste = 6, sum = 20 = 2 × 10 stock length. The conservation check holds, and the math balances.
FFD Is a Heuristic, Not a Certificate
First Fit Decreasing is fast and reproducible but does not prove that the returned stock count or waste is globally minimal. A different arrangement, reusable offcuts, multiple stock lengths, grain direction, defect zones, trim allowances, cut order, clamping, or machine limits can produce a better plan. Pattern-based research on cutting-stock algorithms indexed at doi.org/10.1016/j.cor.2014.03.003 shows why fast heuristics like FFD remain attractive: they scale to large lists and respond quickly to input changes, even when they leave measurable improvement on the table.
The Cut List Optimizer states the heuristic next to the result so a convenient layout is never presented as a mathematical certificate. Treat the output as a planning draft, then confirm the actual stock dimensions including any factory overrun or end trim, the real blade width and kerf behaviour on the chosen material, the measurement tolerance and any setup waste at the start of each stock, and the safe cutting sequence and clamping plan for the saw.
Where This Length Optimizer Is the Wrong Tool
This version is strictly one-dimensional. It does not arrange rectangles on plywood or sheet metal, rotate panels, or model two-dimensional saw paths. Some search phrases use "plywood cutting," but a length-only list cannot safely answer a sheet-layout problem. For plywood, MDF, acrylic sheet, or sheet metal, use dedicated two-dimensional nesting software, especially when grain, rotation, or guillotine-cut constraints matter.
| Scenario | Does this tool fit? | Why or why not |
|---|---|---|
| All parts share one stock length | Yes | FFD sorts and packs against equal stock pieces |
| Parts need plywood or sheet layout | No | Two-dimensional nesting required |
| Mixed stock lengths, such as 8 ft and 10 ft | No | The tool assumes one stock length for every opened piece |
| Reusable offcuts feed future jobs | No | The tool does not return leftovers to inventory |
| Kerf and waste must be visible | Yes | Kerf is added per piece and totals include waste and utilization |
Verify the Plan Before You Cut
The Cut List Optimizer does not replace a shop drawing, machine controller, structural specification, or operator judgment. Use the result as a planning draft, then check that every requested piece appears exactly once in the output, no piece is silently dropped or doubled, and no stock piece exceeds the entered stock length. The conservation check inside the calculator should make that second case impossible. Mark reusable remnants separately, since the displayed waste is simply unused length in this run, not a claim that the offcut has no future value.
Re-run the plan after any input change. Because FFD is deterministic, the same rows in the same order produce the same layout, which is useful for shop audits, reproducibility, and comparing two layouts without guessing which one is current. For boards specifically, the framing-focused walkthrough in the 2x4 Cut List Optimizer guide shows how to translate framing lumber dimensions into a kerf-aware plan with waste and utilization reported next to each stock piece.