Sheets of plywood or OSB for an area
Plywood Calculator
12 ft 6 in × 16 ft, 200 sq ft, lays out as 8 sheets of 4 × 8 (6 whole, 2 cut); buy 8 with 10% waste. Enter your measurements below.
Sources checked
Your estimate
8 sheets to buy
8 laid out (6 whole, 2 cut), 7 with 10% waste; buy the larger.
- Area200 sq ft
- Sheet face4 × 8 ft32 sq ft
- Bare area, no waste6.25 sheets
- Layoutlong edges along the second side8 sheets
- With waste7 sheets
How many sheets of plywood for an area
- The area is 12 ft 6 in × 16 ft, which is 200 sq ft. A 4 × 8 sheet is 32 sq ft of face, so the bare area is 6.25 sheets, or 7 whole sheets. If the room is not a plain rectangle, add up its parts with the square footage calculator.
- Lay the sheets out. Across the 12 ft 6 in side, 4 ft sheets take 4 across: three whole sheets, and a fourth cut to 6 in. Up the 16 ft side, 8 ft sheets take 2 up. That is 8 sheets: 6 whole and 2 cut, with the long edges along the 16 ft side.
- Add the waste. 200 × 1.10 is 220 sq ft, which is 6.875 sheets, so 7 with the waste. The layout needs 8, so buy the larger: 8. The 10% is an example, not a standard.
The panel sizes come from the NIST standard and the Canadian Wood Council’s OSB table. NIST PS 1-22, Structural Plywood (Oct 2023); Canadian Wood Council, OSB sizes and weights, Table 1 (CSA O325)
- Reference panel, PS 1-22 section 5.4
- 48 × 96 inNIST PS 1-22, Structural Plywood (Oct 2023)
- Most common OSB panel
- 4 × 8 ftCanadian Wood Council, OSB sizes and weights, Table 1 (CSA O325)
- Wall sheathing, advisory minimum
- 3/8 PERF CATNIST PS 1-22, Structural Plywood (Oct 2023)
- Span rating example, 32/16
- 32 in roof, 16 in subfloorNIST PS 1-22, Structural Plywood (Oct 2023)
Sheets for common rooms
| Room, feet | Area | Laid out | To buy |
|---|---|---|---|
| 8 × 8 | 64 sq ft | 2 sheets | 3 sheets |
| 8 × 10 | 80 sq ft | 3 sheets | 3 sheets |
| 10 × 12 | 120 sq ft | 6 sheets | 6 sheets |
| 12 × 16 | 192 sq ft | 6 sheets | 7 sheets |
| 16 × 20 | 320 sq ft | 10 sheets | 11 sheets |
| 20 × 24 | 480 sq ft | 15 sheets | 17 sheets |
How much a 4 × 8 OSB sheet weighs
| Nominal thickness | Pounds per sheet |
|---|---|
| 3/8 in | 40 lb |
| 7/16 in | 46 lb |
| 15/32 in | 50 lb |
| 19/32 in | 63 lb |
| 23/32 in | 76 lb |
| 7/8 in | 92 lb |
| 1-1/8 in | 120 lb |
Canadian Wood Council, OSB sizes and weights, Table 1 (CSA O325)
The framing under the sheathing is counted by the board foot calculator, and the sizes of that framing are on the lumber sizes table. A room’s area comes from the square footage calculator.
Plywood questions
How many sheets of plywood do I need for an area?
Start with the area: 200 sq ft for 12 ft 6 in × 16 ft. Divide by the 32 sq ft face of a 4 × 8 sheet and you get 6.25 sheets. Lay the sheets out and the count is 8, with 6 whole and 2 cut. Waste does not change that here, so buy 8.
How big is a sheet of plywood?
A 4 × 8 ft sheet is 32 sq ft. PS 1-22 uses 48 × 96 in (4 × 8 ft) as the reference size for its grade requirements, and says that is not a stated manufacturing size. Check the stamp on the sheet.
Are 4 x 9 and 4 x 10 sheets available?
The Canadian Wood Council says OSB “might also be available” in 4 × 9 and 4 × 10 ft, and no single mill confirms it. Our data has no plywood in those sizes. The sheet count above is only area geometry, so it works for any size, but ask your supplier what they stock.
How much waste should I add?
Our data gives no waste figure. The 10% in the example is a placeholder we chose so the waste line shows; set the percent that fits your cuts and your risk of breakage.
How much does a sheet of OSB weigh?
For a 4 × 8 OSB panel the Canadian Wood Council’s table gives 40 lb at 3/8 in up to 120 lb at 1-1/8 in. CWC calculated those weights from density, not from weighed panels. Our data has no plywood weight, so this page gives none for plywood.
What span rating do I need for a subfloor?
Span rating is two spans: 32/16 means a roof span of 32 in and a subfloor span of 16 in. A rating of 20 is for spans of 19.2 in (PS 1-22 §2.57). Our data gives no floor thickness, so this calculator does not pick one; check the rating against your joist spacing on the plans.
What thickness do I need for wall sheathing?
PS 1-22 notes that the IRC and IBC specify a minimum 3/8 PERF CAT for wall sheathing (section 2.39). It is an advisory note, so confirm the number with your local code.
Does the calculator give a price?
No. Prices vary by mill, region and grade, and our data has none for plywood. Multiply the sheets to buy by your supplier’s price per sheet, and use the board foot calculator if you also need framing lumber.
A planning aid, not an engineering calculation: your local code and building inspector have the final word. Terms