How many cuts from a 2440x1220 sheet of 18mm plywood? Shelving bay worked example

One 2440 × 1220 mm sheet of 18 mm plywood gives you all six parts for a wall-mounted shelving bay, using just 41% of the sheet. The remaining 59% comes off as a single 614 × 2440 mm strip, large enough for a second bay or a future project. The bay in this example is 900 mm tall, 600 mm wide and 300 mm deep: a practical alcove shelf, home-office storage unit, or workshop accessory rack.

Why plywood for shelving?

Structural plywood holds screws well, is significantly stiffer per kilogram than MDF, and its exposed edges can be left as-is (the ply layers look clean when sanded and oiled) or banded with iron-on edge tape. For shelves that will carry real loads, such as books, tool boxes or kitchen appliances, 18 mm ply is a better choice than MDF of the same thickness: it is roughly 30% stiffer across the grain and will not sag as readily over a long span.

The trade-off is surface finish: ply has visible grain and any knots in the face veneer will show through paint unless filled first. For a painted result, MDF is easier. For a natural or oiled finish, ply is the clear choice.

The example shelving bay

Overall outside dimensions: 900 mm tall, 600 mm wide, 300 mm deep. This is an open bay with no back panel, designed to be wall-fixed through the top and bottom panels or through a cleat screwed to the wall. Open shelving does not need a back: it saves material, keeps the bay light, and lets you see what is on the shelf without opening a door.

The two sides run the full height (900 mm) and full depth (300 mm). The top, bottom and two shelves fit between the sides, so their width is 600 minus 2 × 18 = 564 mm. All horizontal members are the full 300 mm deep.

Parts list

Six parts total. Every part is 300 mm in one dimension, which makes the nesting unusually simple.

How all six parts fit on one sheet

Because every part is exactly 300 mm wide, the most efficient nesting is two columns side by side, each 300 mm wide, running the full length of the sheet. A 3 mm saw kerf separates them.

Column A (width 0 to 300 mm):

• Side 1: length 0 to 900 mm.
• Top: length 903 mm to 1467 mm (3 mm kerf after Side 1).
• Shelf 1: length 1470 mm to 2034 mm (3 mm kerf after Top).
• Waste at end of column: 2034 mm to 2440 mm = 406 mm.

Column B (width 303 mm to 603 mm):

• Side 2: length 0 to 900 mm.
• Bottom: length 903 mm to 1467 mm.
• Shelf 2: length 1470 mm to 2034 mm.
• Waste at end: 406 mm (same as Column A).

The two columns use width 0 to 603 mm. The remaining 617 mm of width (from 606 mm to 1220 mm, after the kerf) is one unbroken strip 617 × 2440 mm: enough for a second bay of the same dimensions, or for shelves in a different depth.

Sequence of cuts

1. Make two rip cuts along the full length of the sheet: first at 300 mm, then at 603 mm (300 + 3 kerf + 300). This gives you two 300 mm wide strips and the large 617 mm offcut. Ripping first reduces the sheet to manageable strips before cross-cutting.
2. Cross-cut Strip A at 900 mm (Side 1), then at 1467 mm (Top, 564 mm long), then at 2034 mm (Shelf 1, 564 mm long). Waste end 406 mm.
3. Repeat for Strip B: cross-cut at 900 mm (Side 2), 1467 mm (Bottom), 2034 mm (Shelf 2).

Total saw cuts: 2 rips + 6 cross-cuts = 8 cuts for all six parts. The 406 mm waste ends from each strip are usable for shelf pins, brackets or a small drawer.

Area check

• 2 sides: 2 × (900 × 300) = 540,000 mm²
• Top + bottom: 2 × (564 × 300) = 338,400 mm²
• 2 shelves: 2 × (564 × 300) = 338,400 mm²
• Total: 1,216,800 mm²

Sheet area: 2440 × 1220 = 2,976,800 mm². Utilisation: 40.9%. The remaining 59.1% (1,759,932 mm²) is recoverable offcut.

Shelf spacing

The two shelves divide the internal height into three bays. Internal height between top and bottom: 900 minus 2 × 18 = 864 mm. Three bays at equal spacing: 864 / 3 = 288 mm per bay. Deducting one shelf thickness (18 mm) from each bay gives a clear opening of 270 mm per bay, which suits most books, a standard ring binder standing upright, or smaller workshop accessories.

If you need one taller bay (for example, 400 mm for tall bottles or spray cans), drop one shelf lower and raise the other: the total internal height stays at 864 mm but it divides 400 + 18 + 270 + 18 + 158 = the remaining height distributed to the other two bays. SawReady will re-check the nesting automatically if you change any shelf position.

Extending to multiple bays

MDF vs plywood: which sheet size is the same?

Both MDF and plywood are sold in the same 2440 × 1220 mm standard sheet in the UK. The key differences for a project like this are:

• Weight: 18 mm MDF is around 44 kg per sheet. 18 mm structural plywood is around 32 kg. Ply is easier to carry.
• Screw holding: Plywood holds screws more reliably in the face and edge, particularly with self-tapping screws into the edge. MDF edge-screwing requires pre-drilling and ideally plug inserts.
• Surface: MDF gives a smoother painted finish. Plywood shows grain and may need filling at knots.
• Cost: 18 mm structural ply and 18 mm MDF are similar in price; birch ply costs more. Check current pricing at your local merchant before deciding.

For a shelving unit that will carry real weight and may get knocked about, plywood is the better call. For a painted cabinet in a dry bedroom, MDF works well and machines cleanly.

Plan your own cut list

If your shelving bay is a different size or has more shelves, the method is the same: list every part, note the finished dimensions accounting for panel thickness, and arrange the parts on sheets to find the tightest layout. The two-column approach above works for any project where all parts share a common dimension.

SawReady handles the nesting automatically. Set the sheet to 2440 × 1220 mm, enter your parts, and it shows the most efficient layout and confirms how many sheets to buy.

Plan my shelving cuts