PLYWOOD SHEETS
PLYWOOD / OSB SHEETS
sheets = ⌈(area ÷ sheet) × waste⌉
ft
ft
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RESULT
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FILL IN ABOVE
Standard waste 10%. T&G subfloor loses 3" of width on perimeter sheets — buy at least 1 extra. This is an estimate; not a substitute for plans or shop drawings.
About this calculator
This plywood calculator estimates how many 4-foot-wide sheets of plywood or OSB you need for a subfloor, wall sheathing, or roof deck. Enter the length and width of the area to cover, choose the sheet length (4×8 = 32 ft², 4×9 = 36 ft², 4×10 = 40 ft²), and adjust the waste percentage. Subfloor jobs run 5–10% waste because joists land on a 16" or 24" pattern that aligns well with 4×8 sheets; complex hip roofs and walls with many openings push waste to 12–15%. The calculator rounds up to the nearest whole sheet. For T&G subfloor, allow at least one extra sheet to deal with the tongue lost on the perimeter sheet. ESTIMATE ONLY — measure the actual area and verify your fastening pattern with the engineered plans.
Common questions
How many sheets of plywood do I need for a 24x16 subfloor?
A 24x16 floor is 384 ft². At 32 ft² per 4x8 sheet, that is exactly 12 sheets — but with 10% waste and at least one extra sheet for tongue-and-groove perimeter loss, plan for 14 sheets. The calculator handles the waste math automatically; just measure once and remember to count out an extra sheet when you load the truck. This is an estimate; verify against the engineered floor plan before ordering.
What thickness of plywood for subfloor?
23/32" tongue-and-groove is the standard for residential floors over 16" o.c. joists. 19/32" works on 12" o.c. spacing or where a separate underlayment will be added. 1-1/8" T&G is used on 24" o.c. engineered I-joists. OSB rated as Sturd-I-Floor is acceptable in the same thicknesses. Always match the APA rated stamp on the sheet to the joist spacing called out in the framing plan.
OSB or plywood for sheathing — which is better?
OSB is cheaper, sheathing-rated equivalent, and dominates new construction. Plywood handles repeated wetting better and holds fasteners slightly stronger at the edges, so it is preferred where sheathing will be exposed (e.g., behind cement-board on showers, in unconditioned crawlspaces). For walls and roofs that get covered, OSB is fine. Both are sized identically in this calculator since coverage is the same per sheet.