This plywood calculator counts 4×8 sheets for floors, roofs, walls and projects — area in, sheets out, with waste allowance and a note on coverage per sheet.

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One Sheet = 32 Square Feet — the Rest Is Layout

Buying lumber by volume instead is our Board Foot Calculator. Part of our Construction Calculators collection.

Worked Example (Verified)

  • 20 × 16 ft floor (320 sq ft) (defaults): 320 ÷ 32 = 10.0 sheets exactly; +10% waste → 11 sheets; the no-rip grid layout = ⌈20/8⌉ × ⌈16/4⌉ = 3 × 4 = 12 sheets — the honest range is 11–12 depending on how the room’s cuts fall
  • Roof check: a 1,342 sq ft roof deck (a common 40×30 at 6/12) → 42 sheets net, order 46–47 with waste and ridge/hip cuts
  • Offcut economics: staggering subfloor joints (required for strength) is exactly what consumes the “waste” — it’s structural, not sloppiness

Sheet Goods Discipline

  • Run subfloor/sheathing perpendicular to joists/rafters, stagger end joints, and leave ⅛″ gaps for expansion (the H-clip’s whole career).
  • Match the exposure rating to the job: Exposure 1 for construction delays, Exterior for permanent weather, interior grades for cabinets and underlayment.
  • Actual thickness runs under nominal (¾″ = 23/32″) — stack heights and transitions notice; toe-kicks and CNC plans must.
  • Store flat, acclimate on site, and buy the full count from one stack when grain/appearance matters.

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Frequently Asked Questions

How many sheets of plywood do I need?

Divide your area by 32 (one 4×8 sheet covers 32 sq ft), then add waste: 320 sq ft → 10 sheets net, 11 with 10% waste. If the layout can’t reuse rips, the grid count (rounding each dimension up to sheet multiples) is the safer order — this calculator shows both.

What thickness plywood for a subfloor?

Typically ¾″ (23/32″ actual) tongue-and-groove over 16″ joist spacing, or ⅝″ minimum in some codes; the panel’s span rating stamp is the authority. Tile and stone floors often add ¼″–½″ underlayment/cement board on top — total floor height planning starts with these numbers.

How many sheets for a roof?

Roof area (including pitch factor and overhangs) ÷ 32, plus 10–15% for hips, valleys and ridge cuts. A 1,342 sq ft deck: 42 net → order ~46. Our Roofing Calculator computes the sloped area from footprint and pitch.

Plywood vs OSB — does the count change?

No — same 4×8 footprint, same math. The choice is price/performance: OSB costs less and swells at edges when soaked; plywood costs more, dries faster and holds fasteners near edges better. Many builders sheath roofs in plywood and walls in OSB.

Why is 3/4 plywood actually 23/32?

Sanding and manufacturing standards: modern panels are made slightly under nominal for consistent fits. It matters for dado widths, stacked floor heights and CNC work — measure the sheet, not the label, for joinery.

Is this plywood calculator free?

Yes — free, instant, no sign-up.