Sheet goods are sold under names that are only partly accurate. In North America a 4×8 sheet of plywood is normally 48 × 96 inches, but its thickness is often less than the label says. Elsewhere, sheets are made in metric sizes that are close to, but not exactly, their imperial equivalents. This guide lists the common sizes and real thicknesses, and shows how each one changes a cut list.
Standard sheet sizes
| Sheet | Inches | Millimeters | Where you see it |
|---|---|---|---|
| 4×8 | 48 × 96 | 1219 × 2438 | The North American standard for plywood, MDF, OSB, melamine and particleboard |
| 4×10 | 48 × 120 | 1219 × 3048 | Less common, often special order; useful for parts longer than 8 feet |
| 5×5 | about 60 × 60 | 1525 × 1525 | Baltic birch and similar birch plywood |
| 2440 × 1220 | 96.06 × 48.03 | 2440 × 1220 | The usual 8 × 4 size in the UK and many other metric markets |
| 2500 × 1250 | 98.43 × 49.21 | 2500 × 1250 | Common in Europe for some plywood and MDF |
| 2800 × 2070 | 110.24 × 81.50 | 2800 × 2070 | European chipboard, melamine-faced board and MDF, often cut to order on a panel saw |
| 4×4 and 2×4 | 48 × 48, 24 × 48 | 1219 × 1219, 610 × 1219 | Half sheets and project panels at many home centers |
In Australia and New Zealand, 2400 × 1200 mm sheets are also widely sold alongside 2440 × 1220, so check the listing rather than assuming. Large European boards such as 2800 × 2070 are heavy and awkward to handle at home; buyers often have them cut to rough size at the supplier.
Nominal versus actual thickness
Most North American plywood is thinner than its nominal size. The thickness stamped on the sheet or printed on the label is often a fraction such as 23/32 rather than 3/4. Baltic birch and other imported birch plywood is made in metric thicknesses and sometimes sold under inch names. MDF is usually close to its nominal thickness. The figures below are typical; individual sheets and batches vary by a few thousandths of an inch, so measure your own material with calipers at several points away from the edges.
| Sold as | Typical actual | Decimal (in) | Millimeters |
|---|---|---|---|
| 1/4 in plywood | 7/32 in, or 5.2 mm | 0.219 or 0.205 | 5.2 to 5.6 |
| 3/8 in plywood | 11/32 in | 0.344 | 8.7 |
| 1/2 in plywood | 15/32 in | 0.469 | 11.9 |
| 5/8 in plywood | 19/32 in | 0.594 | 15.1 |
| 3/4 in plywood | 23/32 in | 0.703 | 17.9 |
| 1/4 in Baltic birch | 6 mm | 0.236 | 6 |
| 1/2 in Baltic birch | 12 mm | 0.472 | 12 |
| 3/4 in Baltic birch | 18 mm | 0.709 | 18 |
| 3/4 in MDF | close to 3/4 in | about 0.75 | about 19 |
In metric markets MDF and particleboard are usually sold by their metric thickness, such as 18 mm, rather than under inch names.
Why the real thickness matters
Dados and rabbets. A 3/4-inch router bit or dado stack cuts a groove about 3/64 inch (1.2 mm) wider than 23/32 plywood. The joint looks loose and has less glue contact. Undersized plywood bits (sold in sizes such as 23/32 inch), shims in a dado stack, or two passes with a narrower cutter all solve it. Test-cut in scrap from the same sheet.
Overall dimensions. Thickness errors stack. A cabinet drawn with two 3/4-inch sides around a fixed inside width ends up 1/16 inch narrower overall if the sides are 23/32. Repeat that across a run of cabinets and it becomes visible. Design with the measured thickness, or fix the dimension that matters most, usually the inside width that drawers and doors depend on, and let the others float.
Grooves for thin panels. A groove cut with a 1/4-inch bit is loose on a 6 mm (0.236 inch) panel and looser still on 5.2 mm. Size grooves for back and bottom panels from the panel you will actually use.
Oversize sheets and edge trim
Some suppliers sell MDF and some other panels slightly oversize, for example 49 × 97 inches, so a full 48 × 96 can be cut after trimming damaged edges. Measure a new sheet before you lay out parts. If it is oversize, enter the real size; if the edges are damaged, use edge trim rather than hoping the layout misses the dents.
Metric 2440 × 1220 mm sheets are about 1/16 inch longer and 1/32 inch wider than 96 × 48. That is rarely enough for an extra part, but it can absorb a kerf.
How sheet size changes yield
Parts that fit well on one sheet size can fit badly on another, and the kerf is often the deciding detail.
- 24-inch-deep cabinet parts. Two 24-inch rips need 48 1/8 inches with a 1/8-inch kerf, so a 48-inch sheet gives one 24-inch strip and one 23 7/8-inch strip. That is one reason many cabinet plans use box depths a little under 24 inches.
- Long parts. Anything over 96 inches needs a 4×10 sheet or a joint. Tall pantry or wardrobe sides at 84 inches fit on a 4×8 and leave an offcut just under 12 inches long.
- Square sheets. On a 60-inch sheet, two parts across can each be up to 29 15/16 inches wide with a 1/8-inch kerf, and three can be up to 19 29/32 inches. Two 30-inch parts end to end will not fit.
The figure compares ten 29 × 11 1/2-inch shelves on a 4×8 sheet and on a 5×5 sheet, with a 1/8-inch kerf. The shelves cover 3,335 square inches. That is about 72% of the 4,608 square inches in a 4×8, which leaves a long offcut, and about 93% of the 3,600 square inches in a 5×5. If the leftover from the 4×8 has no use, the smaller sheet is the better buy; if it does, the 4×8 gives you material for the next project.
Price per square foot settles the rest. A 4×8 has 32 square feet and a 5×5 about 25, so divide each sheet's price by its area before comparing. To test your own parts list on several sheet sizes, try each size in the plywood calculator and compare the sheet counts and waste.