How Many Sheets of Plywood Do I Need? 4x8 Sheets by Area
Part of the project planners: Planning a shed, pergola, garage slab or coop and Planning a roof replacement.
A 4 × 8 ft sheet of plywood covers 32 square feet. A 16 × 12 ft floor (192 ft²) needs 7 sheets by area with 10% waste, or 6 in a layout of whole sheets. The plywood calculator handles circles, other sheet sizes and two layers.
Sheets of 4×8 plywood by size
With 10% waste; the grid column lays whole sheets without reusing cutoffs:
| Area | Square feet | Sheets (by area) | Sheets (grid) | Two layers |
|---|---|---|---|---|
| 8 × 8 ft | 64 ft² | 3 | 2 | 5 |
| 10 × 12 ft | 120 ft² | 5 | 6 | 9 |
| 12 × 12 ft | 144 ft² | 5 | 6 | 10 |
| 12 × 16 ft | 192 ft² | 7 | 6 | 14 |
| 16 × 20 ft | 320 ft² | 11 | 10 | 22 |
| 20 × 24 ft | 480 ft² | 17 | 15 | 33 |
| 24 × 24 ft | 576 ft² | 20 | 18 | 40 |
Sheet sizes
For the 16 × 12 ft floor:
| Sheet | Area | Sheets needed |
|---|---|---|
| 4 × 8 ft | 32 ft² | 7 |
| 4 × 10 ft | 40 ft² | 6 |
| 4 × 12 ft | 48 ft² | 5 |
How to count
- Work out the area to cover in square feet.
- Divide by the area of one sheet, and add about 10% for waste.
- For a floor or roof, lay out the sheets on a drawing: they run across the joists or rafters, with the end joints staggered over a joist.
- For a roof, use the sloped area, not the floor area.
- Round up, and buy one extra for mistakes if the job is large.
Choosing plywood
- Subfloor: 3/4 inch tongue-and-groove plywood or OSB on joists at 16 inch centers.
- Roof sheathing: 1/2 inch plywood or 7/16 inch OSB on rafters at 24 inch centers, in many areas.
- Walls: 7/16 to 1/2 inch sheathing.
- Outdoors: use exterior-grade plywood or treated panels, and seal the edges.
See also the roofing calculator for the roof area. Estimates only: check your local code and the span rating on the panel.
Frequently asked questions
How many square feet is a sheet of plywood?
A 4 × 8 ft sheet is 32 square feet. A 4 × 10 sheet is 40, and a 4 × 12 sheet is 48.
How many sheets of plywood for a 16x12 floor?
7 sheets of 4 × 8 ft by area with 10% waste (6 for a whole-sheet layout), for 192 ft². Two layers need 14.
How many sheets for a roof?
Divide the roof area (not the floor area, since the slope adds to it) by 32 and add 10% for waste. Use the roofing calculator for the area at your pitch.
How do I allow for waste?
Add 10% for cuts, or lay it out sheet by sheet. A whole-sheet layout for a big rectangle may need fewer than the area suggests, but short pieces have to meet on joists.
Should plywood joints be staggered?
Yes. Stagger the end joints by at least 2 feet (a half sheet is the easy way), and on a floor glue and screw the sheets, with the long edges across the joists.
More guides
Tools & materials for this project
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and follow local building codes for anything structural.