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Plywood & OSB sheathing calculator

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12 sheets384.00 SF ÷ 32 SF per sheet
Area to cover
384.00 SF
Sheets (by area)
12 sheets
Laid out sheet by sheet
12 sheets (4 × 3)
Nails per sheet
43 nails
Nails in all
516 nails

These sketches are here to help you order material and price the work quickly. They are not engineered or shop drawings — always build from your approved project drawings.

Sheet size
Framing spacing (OC)

IRC Table R602.3(1): 6" at panel edges, 12" in the field (6" in the field for roofs with 8d common nails since the 2021 IRC). Shear walls and high-wind areas need closer nailing — follow the plans.

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  1. Area
    length × width
    24' 0" × 16' 0" = 384.00 SF
  2. Sheets
    area ÷ sheet SF, rounded up
    384.00 SF ÷ 32.00 SF = 12
  3. Laid out sheet by sheet
    (width ÷ sheet width, rounded up) × (length ÷ sheet length, rounded up)
    ( 16' 0" ÷ 4' 0" ) × ( 24' 0" ÷ 8' 0" ) = 12
  4. Framing lines under a sheet
    sheet ÷ framing spacing, rounded up, + 1
    96 ÷ 16 (in), rounded up, + 1 = 7
  5. Nails per sheet
    2 edge lines × (width ÷ edge spacing + 1) + middle lines × (width ÷ field spacing + 1)
    2 × (48 ÷ 6 + 1) + 5 × (48 ÷ 12 + 1) (in) = 43
  6. Nails in all
    nails per sheet × sheets
    43 × 12 = 516

Where the numbers come from

  • Sheets: Area ÷ sheet SF (4' × 8' = 32 SF), rounded up. Laid out: whole sheets per row × rows, offcuts not reusedThe area count assumes offcuts get used elsewhere; the layout count is the most you would need for a plain rectangle. Floors and roofs: long side across the joists or rafters, end joints staggered (APA). Walls: sheets stand up, openings sheathed over and cut out. Same area rule as the wall-framing page.Source
  • Roof area: Plan area × √(1 + (rise ÷ 12)²) — 6/12: √1.25 = 1.1180Worked out from the right triangle of rise and run: a 12" run at 6" rise is √(12² + 6²) = 13.42" of rafter, 13.42 ÷ 12 = 1.118. Measure the plan width eave to eave including overhangs. The layout assumes a gable roof (two planes); a hip roof has the same area but more cuts.
  • Nail spacing: IRC Table R602.3(1): 6" at supported panel edges, 12" at intermediate supports; roof field 6" with 8d common nails since the 2021 IRCThe linked table is the 2012 IRC text (6" edges / 12" field for subfloor, roof and wall sheathing; high-wind footnotes call for tighter roof nailing). The 2021 IRC cut roof field spacing to 6" for 8d common and RSRS-01 nails (12" kept for 10d common or 8d deformed shank) — Simpson Strong-Tie summary: https://seblog.strongtie.com/?p=5097. Floor edges perpendicular to the joists usually aren't blocked (T&G), so only the framing lines get nails. Braced walls, shear walls and high-wind or seismic areas need closer nailing — follow the plans.Source

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This is a community calculator for the construction trades. We check every number against its source, but mistakes happen. If a number looks wrong, tell us — and tell us which calculator you want next.

Sheets of plywood or OSB for a subfloor, a wall or a gable roof — by area and laid out sheet by sheet, with nails per sheet.

The formula

Sheets = area ÷ sheet SF (4' × 8' = 32 SF), rounded up. Roof area = plan length × plan width × √(1 + (rise ÷ 12)²). Laid out: rows × sheets per row, whole sheets, offcuts not reused. Nails per sheet: each framing line under the sheet gets a row — the two edge lines at 6", the middle lines at the field spacing.

Worked example

A 24' × 16' floor is 384 SF ÷ 32 = 12 sheets of 4×8 (4 rows × 3). At 16" OC a sheet lands on 96 ÷ 16 + 1 = 7 joists: 2 × 9 nails at the ends + 5 × 5 in the field = 43 nails, 516 in all. The same footprint as a 6/12 roof: 384 × √1.25 = 429.3 SF ÷ 32 = 13.4 → 14 sheets; each side is 8 × 1.118 = 8.94' eave to ridge, so laid out it takes 2 × 3 rows × 3 = 18 sheets if no offcut is reused.

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