Guillotine Cut vs Standard (Shelf) Cut: Which Algorithm Should You Use?

Every cut list optimizer uses an algorithm to arrange parts on sheets. The algorithm you choose determines not just how much material you save — it determines whether you can actually execute the layout with your equipment. Pick the wrong one, and you'll end up with a cutting diagram that looks great on screen but can't be cut on your saw.

If you've ever used a cut list optimizer and noticed an option to choose between different algorithms — Guillotine, Standard, Shelf, or similar — you've probably wondered what the difference is. Most software doesn't explain it well. You click one, you click the other, the layouts look slightly different, and you move on.

But this choice has real consequences. It affects your material yield, the number of sheets you buy, and whether the cutting plan is physically executable in your workshop. This guide explains both approaches in plain language, shows you what each layout looks like in practice, and helps you pick the right one for your equipment and workflow.

What Is a Guillotine Cut?

A guillotine cut is a straight cut that runs from one edge of the sheet to the opposite edge, dividing the sheet into two separate pieces. The name comes from the paper guillotine — the cutter that slices through an entire stack of paper in one motion, edge to edge.

The critical constraint is this: every cut must go all the way across. You cannot stop a cut partway through the sheet. You cannot cut an L-shape. You cannot cut around a corner. Each cut produces two rectangles, and each of those rectangles can then be cut again with another edge-to-edge cut.

This is exactly how a panel saw works — both vertical panel saws and sliding table saws. When you push a sheet through a table saw, the blade travels from one edge to the other. You can't stop the blade in the middle of the sheet and redirect it. The same applies to a vertical panel saw: the blade carriage moves from top to bottom (or left to right), cutting the full width or height of the panel.

A guillotine cutting pattern is built recursively. You start with a full sheet. You make one cut, splitting it into two pieces. Then you take one of those pieces and make another cut, splitting it into two smaller pieces. At each step, every cut crosses the entire width or height of the piece being cut. The process continues until you've isolated every individual part.

What a Guillotine Layout Looks Like

In a guillotine layout, you'll notice a distinct visual pattern: the sheet is divided into horizontal or vertical strips first, and then each strip is subdivided into individual parts. There's a clear hierarchy of cuts — primary cuts create strips, secondary cuts separate parts within those strips.

This means some space between parts may go unused. If two adjacent parts in a strip have different heights, the strip height is determined by the taller part, and the shorter part leaves a gap. The algorithm can't fill that gap with another part from a different strip, because doing so would require a non-edge-to-edge cut.

Stages in Guillotine Cutting

Guillotine algorithms are often described by the number of "stages" they use:

Two-stage guillotine: The sheet is first cut into horizontal strips (stage 1), and then each strip is cut into individual parts (stage 2). This is the simplest form and the easiest to execute — you make all your rip cuts first, then all your cross cuts. Many panel saws in cabinet shops follow exactly this workflow.

Three-stage guillotine: After the two-stage cuts, the algorithm allows one more round of cuts to further subdivide pieces. This adds flexibility and can improve material yield, but the cutting sequence becomes more complex.

Multi-stage (free) guillotine: No limit on the number of stages. The algorithm can recursively subdivide as many times as needed, as long as every cut is edge-to-edge. This gives the best yield among guillotine methods but produces a more complex cutting sequence.

CutGrid's Guillotine algorithm generates multi-stage guillotine patterns — giving you the best possible yield while ensuring every cut can be executed on a panel saw.

What Is a Standard (Shelf) Cut?

A Standard algorithm — often called a Shelf algorithm in the academic literature — takes a different approach. Instead of requiring every cut to go edge to edge, it arranges parts in horizontal rows (shelves) across the sheet, and then places parts within each shelf side by side. When one shelf is full, a new shelf is started above it.

The key difference: parts within a shelf don't all have to be the same height. The algorithm can place a tall part next to a short part and then fill the space above the short part with another small piece. This is something a guillotine algorithm cannot do, because filling that space would require a cut that doesn't go edge to edge.

This flexibility means the Standard algorithm can often fit more parts on a sheet than a Guillotine algorithm can. It packs tighter because it's allowed to use spaces that a guillotine layout must leave empty.

What a Standard Layout Looks Like

In a Standard layout, you'll see parts arranged more freely across the sheet. Parts of different sizes sit next to each other without the strict strip structure of a guillotine layout. The layout looks "tighter" — there's less visible empty space between parts. You may see smaller parts tucked into corners or gaps that a guillotine layout would have left as waste.

However, if you look carefully, you'll notice that some of the cuts required to separate these parts don't go from edge to edge. To extract a small part that's tucked next to a taller part, you'd need to make a partial cut — starting at one edge but stopping partway across the sheet.

Can You Execute a Standard Layout on a Panel Saw?

This is the central question. On a panel saw, every cut goes edge to edge — that's the physical reality of the machine. So a Standard layout, which may require partial cuts, can't always be executed directly on a panel saw.

However, this doesn't make Standard layouts useless for panel saw users. Here's why:

Many Standard layouts are partially guillotine-compatible. The algorithm may produce a layout where 90% of the cuts are edge-to-edge, with only a few parts requiring partial cuts. In practice, you can often execute most of the layout on your panel saw and handle the remaining few parts with a secondary tool — a circular saw, a jigsaw, or even a second pass on the table saw after repositioning.

CNC routers have no edge-to-edge constraint. If you're using a CNC router, the cutting head can start and stop anywhere on the sheet. Every Standard layout is fully executable on a CNC — and you get the benefit of higher material yield.

Some shops use a hybrid workflow. They run the primary breakdown on a panel saw (the large edge-to-edge cuts), then move the sub-panels to a table saw or CNC for the secondary cuts that aren't edge-to-edge.

Side-by-Side Comparison

Let's make the differences concrete. Imagine you need to cut the following parts from a 2440 × 1220 mm sheet of 18 mm MDF, with a 3 mm kerf:

• 2 × 800 × 400 mm

• 3 × 600 × 300 mm

• 4 × 400 × 250 mm

• 2 × 350 × 200 mm

• 3 × 200 × 150 mm

With a Guillotine algorithm, the sheet is divided into strips. The two large 800 × 400 parts go in the first strip. The 600 × 300 parts fill the next strip. The smaller parts fill subsequent strips. Because each strip's height is set by the tallest part in it, there are gaps next to shorter parts. Total waste might be 18 – 22%.

With a Standard algorithm, the same parts are arranged more flexibly. The 200 × 150 parts can be tucked into the space next to the 600 × 300 parts. The 350 × 200 parts can fill gaps that the Guillotine layout would have left empty. Total waste might be 12 – 16%.

That's a 4 – 8% difference in material utilization — on a single sheet. Across a full project with multiple sheets, this can mean one fewer sheet purchased.

When to Use Each Algorithm

Use Guillotine when:

You're cutting on a panel saw. This is the primary reason. If your workshop's main cutting tool is a vertical panel saw, a sliding table saw, or a beam saw, you need edge-to-edge cuts. A Guillotine layout guarantees that every cut in the diagram can be executed on your machine without workarounds.

You're outsourcing to a cutting service. Most commercial cutting services (lumber yards, hardware stores, panel cutting shops) use panel saws. If you're sending your cutting plan to someone else, a Guillotine layout ensures they can follow it exactly.

Simplicity matters more than yield. Guillotine layouts have a natural cutting sequence: make the long cuts first, then the shorter cuts. There's no ambiguity about which cut to make next. For less experienced operators, or for shops where cutting speed matters more than squeezing out the last 2% of yield, Guillotine is the safer choice.

You're cutting glass. Glass is almost always cut using guillotine patterns. You score and snap along straight lines, edge to edge. Partial cuts in glass are impractical and risk cracking the sheet unpredictably.

Use Standard (Shelf) when:

You're cutting on a CNC router. A CNC has no edge-to-edge constraint. The cutting head moves freely in X and Y. Standard layouts give you better yield with no downside — the CNC can execute any arrangement the algorithm produces.

Material cost is the priority. If you're working with expensive sheet material — hardwood veneer plywood, specialty laminates, metal sheets — and every percentage point of waste matters, Standard will consistently give you better yield than Guillotine.

You have a hybrid workflow. If your shop has both a panel saw and a table saw (or a CNC), you can use Standard layouts and split the cutting between machines. The panel saw handles the primary breakdown, and the secondary tool handles any non-guillotine cuts.

Part sizes vary widely. Standard algorithms are particularly better than Guillotine when your parts list has a wide range of sizes — large parts mixed with very small parts. The small parts can fill gaps that a Guillotine layout would waste. If all your parts are similar in size, the difference between the two algorithms shrinks.

The Yield Difference: How Much Does It Really Matter?

The yield difference between Guillotine and Standard varies depending on your parts list. Here's what to expect in practice:

Parts of similar sizes (e.g., all shelves for identical cabinets): The difference is small — typically 1 – 3%. Guillotine handles uniform parts almost as well as Standard because the strip structure naturally accommodates similar-sized parts.

Mixed part sizes (e.g., a cabinet project with sides, shelves, doors, drawer fronts, and filler strips): The difference grows to 4 – 8%. Standard fills gaps with small parts that Guillotine can't place efficiently.

Highly varied part sizes with many small pieces: The difference can reach 8 – 12%. This is where Standard really shines — it uses small parts as "gap fillers" across the sheet.

For a single sheet at $50 – $80, a 5% yield improvement might save a few dollars. But across a full kitchen cabinet project using 6 – 10 sheets, that 5% often translates to one full sheet saved — $50 – $80 in pure material savings. Across a year of projects, the difference compounds significantly.

A Note on Terminology

Different software uses different names for these algorithms, which can be confusing. Here's a quick translation guide:

In CutGrid, the options are labeled Guillotine and Standard (Shelf) to make the distinction clear.

How CutGrid Handles Both Algorithms

CutGrid lets you switch between Guillotine and Standard with a single click in the Cutting Parameters panel. You can run both algorithms on the same parts list, compare the layouts side by side, and choose the one that best fits your equipment and project.

Both algorithms respect all your other parameters — kerf width, trim margins, grain direction, and part rotation settings. The only difference is the placement constraint: edge-to-edge cuts or flexible placement.

A practical workflow many CutGrid users follow: run Guillotine first to get a baseline. Then run Standard to see if the yield improvement justifies the extra cutting complexity. If Standard saves you a sheet, it's probably worth the slightly more complex cutting sequence. If it only saves 1 – 2%, stick with Guillotine for simplicity.

Practical Tips

Always match the algorithm to your saw. If your shop only has a panel saw, always use Guillotine. A beautiful Standard layout is useless if you can't execute it.

Try both before buying material. It takes two seconds to switch algorithms in CutGrid and re-optimize. If Standard saves a sheet, you've just paid for your subscription with a single project.

For cutting services, always export Guillotine. Even if you own a CNC, if you're sending a cutting plan to an outside service, assume they're using a panel saw unless you've confirmed otherwise.

Glass is always Guillotine. Scoring and snapping glass requires full edge-to-edge lines. Standard layouts with partial cuts are not safe for glass — the sheet can crack unpredictably along unintended lines.

Don't overthink it for small projects. If you're cutting 5 – 10 parts from a single sheet, the yield difference between algorithms is typically negligible. The algorithm choice matters most on large projects with many parts across multiple sheets.

Key Takeaways

Guillotine = every cut goes edge to edge. This matches how panel saws, beam saws, and glass scoring work. It's the safe choice for any saw-based workshop.

Standard (Shelf) = flexible placement, potentially partial cuts. This gives better material yield but may require a CNC or a secondary tool for some cuts.

The yield difference is typically 3 – 8%, depending on how varied your part sizes are. On multi-sheet projects, this often means one fewer sheet purchased.

Match the algorithm to your equipment. Guillotine for panel saws. Standard for CNC. Either works if you have both — run both and compare.

See the Difference on Your Own Parts

Enter your cut list in CutGrid, run both algorithms, and compare the layouts side by side. The yield difference might surprise you.

Try Both Algorithms Free →