Plywood Sizes: Standard Sheet Dimensions, Thickness and Weight

A standard plywood sheet is 4 × 8 ft (32 sq ft); 4 × 9 and 4 × 10 ft sheets also exist. A sheet sold as 3/4 in is the 23/32 category and weighs roughly 70 to 80 lb by a dated table.

A 4 × 8 sheet covers 32 sq ft. A wall of 234 sq ft net takes 234 ÷ 32 = 7.3, so 8 sheets, or 9 with a 10% allowance for cuts. At 44.8 to 54.4 lb per 15/32 sheet, those 9 sheets weigh about 403 to 490 lb.

What size is a sheet of plywood?

4 × 8 feet is the standard. APA, the engineered wood trade association, says standard OSB panels are 4 × 8 ft, with oversized panels up to 8 × 24 ft for panelized systems, SIP facers and modular floors. Weyerhaeuser states that its southern yellow pine plywood panels are all 4 × 8 ft. Longer panels exist: Georgia-Pacific lists its OSB sheathing in sizes for 4 × 8, 4 × 9 and 4 × 10 ft, with custom panels up to 26 ft. The area of any sheet is width times length:

sheet area (sq ft) = width (ft) × length (ft)
4 × 8 = 32     4 × 9 = 36     4 × 10 = 40     4 × 12 = 48

Panels are made a little under nominal. Georgia-Pacific’s square-edge OSB “sized for 4 × 8” measures 3 ft 11-7/8 in × 7 ft 11-7/8 in, which is 47.875 × 95.875 in, or 31.875 sq ft. Tongue-and-groove panels are 3 ft 11-1/2 in wide, because the tongue is not counted. The trade and this guide count a full 32 sq ft, a difference of 0.4%. Availability of 4 × 9, 4 × 10 and longer sheets varies by region and by supplier, so ask yours before you plan the layout around them.

Is 3/4 plywood really 3/4 inch thick?

No. Since 2008, APA says, structural panels carry two thickness designations. The Performance Category is the nominal thickness that building codes (IBC and IRC) use. The decimal thickness designation is the one used for packaging and labeling. The Performance Category is also the name in the store: a panel stamped 23/32 category is sold as 3/4 in, and a 15/32 category panel is sold as 1/2 in or 15/32 in.

The allowed range comes from product standard PS 2-10, as printed in a Huber Engineered Woods technical tip: plus or minus 1/32 in on categories up to 13/16 in, and plus or minus 5% above that. Each mill then declares its own decimal. The third column below is one mill’s example, Georgia-Pacific’s BlueRibbon OSB sheathing, not a rule for every panel, and another mill’s plywood can print a different number inside the range.

So a “3/4 in” sheet of the 23/32 category measures about 0.70 in with this mill (0.703 in), which is 0.016 in under its fraction of 0.7188 and inside the tolerance. A “1/2 in” 15/32 sheet measures about 0.45 in (0.451 in). The 15/32 range in the table is calculated from the 1/32 tolerance, because the Huber table does not list that category. Measure the panel you are buying when a flush edge matters, for example when you mix plywood and OSB or match a neighboring floor.

How much does a sheet of plywood weigh?

Weight depends on thickness, species, glue and moisture, so manufacturers publish no single figure. The only manufacturer table behind this guide is Boise Cascade’s technical note GE-1, “Weights of Building Materials”, which gives pounds per square foot (psf) for wood structural panels. Its footnote cites APA’s Technical Topic TT-019 from 1998, and the note itself was valid for two years past its publish date, so the table is old and past its stated validity. It also gives one range for “Plywood – OSB” and does not separate the two. Use it for planning, and use the label or the supplier’s data for an exact weight.

weight of one sheet (lb) = sheet area (sq ft) × psf
4 × 8:  32 × psf     4 × 10:  40 × psf

The psf column is from the table, and the sheet weights are the psf range times 32 or 40 sq ft. Treat the result as a range. It helps you plan how many people lift a 3/4 in sheet or how much a load of panels adds up to, but it is not a structural dead load for a design.

How many sheets of plywood do I need?

Divide the area to cover by the area of one sheet, add an allowance for cuts, and round up. The allowance is a convention, not a standard: a commercial building-materials marketplace (Billd) uses 10% for subfloor and roof sheathing and 15 to 20% for custom cuts, and this guide uses 10% as a default.

sheets = ceil( area × (1 + waste) ÷ sheet area )
roof area = plan area × √(1 + (rise ÷ 12)²)
wall area = Σ(length × height) + gable triangles − openings

Two examples show where the rounding bites.

• Wall, 30 × 9 ft with two 3 × 6 ft windows. Gross area 30 × 9 = 270 sq ft. Openings 2 × 18 = 36 sq ft. Net 270 − 36 = 234 sq ft. Without an allowance, 234 ÷ 32 = 7.31, so 8 sheets. With 10%, 234 × 1.10 ÷ 32 = 8.04, so 9 sheets. With 4 × 9 sheets, 234 ÷ 36 = 6.5 gives 7 sheets, and 234 × 1.10 ÷ 36 = 7.15 gives 8.
• Roof, 24 × 40 ft plan with a 6/12 pitch. The plan area, overhangs included, is 960 sq ft. The pitch factor is √(1 + 0.5²) = 1.1180, so the roof area is 960 × 1.1180 = 1,073.3 sq ft. Without an allowance, 1,073.3 ÷ 32 = 33.54, so 34 sheets. With 10%, 1,073.3 × 1.10 ÷ 32 = 36.9, so 37 sheets. The roof square footage guide explains the pitch factor.

Weight of the roof example in 15/32 panels: 37 sheets × 32 sq ft × 1.4 psf = 1,658 lb, and × 1.7 psf = 2,013 lb, so about 1,658 to 2,013 lb. These are area-based counts. Real counts depend on the layout, on how you cut around openings, and on whether the supplier sells by the sheet or by the unit.

Which thickness should you buy?

This guide does not tell you. The thickness, the span rating printed on the grade stamp (the pair of numbers such as 24/16), the nailing, and the edge support between joists or rafters depend on your framing spacing, loads and local code. They are structural choices, and the numbers in this guide are for sizing and ordering only.

Assumptions, common errors and limits

• Counts use a nominal 32 sq ft per 4 × 8 sheet. The real panel is about 0.4% smaller, which does not change a count except on a borderline job.
• Taking the fraction as the thickness. A 3/4 in sheet is about 0.70 in by one mill’s declaration. Do not size a dado, a rabbet or a door gap on the fraction.
• Using one mill’s decimals for every panel. The decimals in this guide are Georgia-Pacific’s OSB. Plywood from another mill can print a different number inside the allowed range.
• Treating the weight table as exact. It is a range, it dates from a 1998 APA topic, and it does not separate plywood from OSB. A wet sheet weighs more.
• Counting the roof at plan area. Multiply by the pitch factor first, and include the overhangs.
• Forgetting openings. Subtract windows and doors from a wall, but remember that the cut-outs are rarely reusable.
• The 10% allowance rests on one commercial source. Raise it for many cuts, openings or a diagonal layout.
• Sheet sizes and thicknesses vary by region and by supplier. Check the stamp and the unit label.

Common questions