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Drywall, Flooring & Interior

Plywood Calculator

Sheet count for floors, walls, roofs and sheathing, with an allowance for cuts.

Your measurements

Run each surface separately — a floor and a roof deck are different orders.

Surface
Application sets the thickness suggestion and the fastener spacing below.
Sheet and openings

Your result

Sample values

27

Sheets

768

Area, ft²

9

Pounds of screws

2,110

Pounds, delivered weight

4 × 8 sheets in 3/4 in tongue and groove, 10% waste.

What to order

Item Quantity
3/4 in T&G sheets 27
Subfloor adhesive 9 tubes
2 in deck screws 9 lb
Approximate weight 2,110 lb

How to use this calculator

Enter the surface you are sheathing and deduct any openings such as a stairwell. Run floors, walls and roof decks as separate calculations, because they usually take different thicknesses and different fastener patterns.

The waste allowance covers cuts at the perimeter and the staggering of joints. Sheets must be laid with their long edge across the framing and end joints staggered between rows, which means cutting the first sheet of alternate rows in half — that alone is most of the ten percent.

Formula

Net area = (Length × Width) − Openings

Sheets = Net area ÷ Sheet area × (1 + Waste)

Sheet area
32 ft² for a standard 4 × 8 sheet
Waste
perimeter cuts and staggered end joints

Round up to whole sheets — plywood is not sold cut to size.

Worked example

A 32 ft by 24 ft subfloor in 3/4 in tongue and groove, no openings, 10% waste.

  1. 32 ft × 24 ft = 768 ft²
  2. 768 ÷ 32 ft² per sheet = 24 sheets
  3. 24 × 1.10 = 26.4 sheets
  4. Rounded up to 27 whole sheets
  5. 27 sheets × 78 lb each = 2,110 lb

27 sheets, about 2,110 lb delivered

Understanding your results

Weight is worth checking before delivery day. Twenty-seven sheets of three quarter inch ply is over a ton, and a single sheet at 78 lb is awkward for one person on a ladder. If the material is going upstairs or onto a roof, that figure decides whether you need help or a lift.

Tongue and groove costs more per sheet and is worth it on floors. The joint transfers load between sheets at the unsupported edges, which is what stops the squeaks and soft spots that show up a year after the floor covering goes down.

Questions

About this calculator

Ask something else

Three quarter inch tongue and groove over joists at 16 in centres is the common standard. At 24 in centres you want a thicker or rated panel. Check the span rating stamped on the sheet against your joist spacing rather than going by thickness alone.

For most sheathing they perform similarly and OSB is cheaper. Plywood dries faster after wetting and holds fasteners better at the edges, which matters on a floor that may be exposed during construction or in a wet climate. OSB swells at cut edges if it gets soaked.

Long edge perpendicular to the framing, with end joints staggered between rows so no four corners meet. That orientation uses the panel strength axis across the span and spreads the joints, which is what the span ratings assume.

Yes. Construction adhesive between joist and sheet, screwed rather than nailed, is the single most effective thing you can do to prevent squeaks. One tube covers roughly three sheets, which is where the tube count comes from.

Keep going

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Estimates, not specifications. Results are based on the values you enter and on typical material properties. Densities, coverage rates and product sizes vary between suppliers, so confirm quantities against your supplier's data before ordering. Structural work must be signed off by a qualified professional and meet your local building code.