How much plywood do I need for a 15 × 17 ft floor?

With standard 4×8 ft sheets and a 10% waste factor, you need about 9 sheets. (15×17 = 255 ft², 255×1.10 = 280.5 ft², 280.5 ÷ 32 ≈ 8.76 → round up to 9.)

How many square feet does a 4×8 sheet cover?

A 4×8 sheet covers 32 ft². In metric terms that is about 2.97 m².

How can I estimate plywood cost to cover an area?

Calculate area, add waste, convert to sheet count, then multiply sheets × sheet area × price per area. Always round sheets up to a whole number.

Plywood Calculator

Plywood / Sheathing Sheet Calculator

Estimate how many plywood (or OSB) sheets to buy for a surface — plus an estimated waste amount and total cost. Enter the surface length and width, then (optionally) set the sheet size, price per area, and waste factor.

Plywood / Sheathing Calculator

Estimate sheet count from area, sheet size, and waste

Surface length

Surface width

Waste factor

Plywood price (per area)

Sheet size

Sheet length

Sheet width

Results

Enter dimensions above to calculate

Formulas used

This calculator uses basic area math, then adds waste and rounds up to whole sheets.

1. Calculate surface area

Formula:

Area = Length × Width

Enter the length and width of the surface you want to cover. This works for floors, roof decks, wall sheathing, and any rectangular surface.

2. Calculate sheet coverage

Formula:

Sheet area = Sheet length × Sheet width

Use a standard sheet (e.g., 4×8 ft or 1.22×2.44 m) or enter a custom size.

3. Add waste factor

Formula:

Area with waste = Area × (1 + Waste%)

Waste accounts for cut-offs, mistakes, and unusable pieces. 10% is a common baseline for simple layouts.

4. Convert area to sheet count

Formula:

Sheets = ceil(Area with waste ÷ Sheet area)

You always round up to a whole sheet because you can’t purchase fractions of a sheet.

5. Estimate total cost

Formula:

Total cost = Sheets × Sheet area × Price per area

Enter a price per square metre or per square foot (depending on your unit system).

Example

Living room floor: length 6 m, width 4 m. Sheet 1.30 m × 0.20 m (0.26 m²). Price 10 per m². Waste factor 10%.

Total area = 6 × 4 = 24.00 m²
Area with waste = 24.00 × 1.10 = 26.40 m²
Sheets = 26.40 ÷ 0.26 = 101.54 → 102 sheets
Cost = 102 × 0.26 × 10 = 265.20

Frequently Asked Questions

How much plywood do I need for a 15 × 17 ft floor?: With standard 4×8 ft sheets and a 10% waste factor, you need about 9 sheets. (15×17 = 255 ft², 255×1.10 = 280.5 ft², 280.5 ÷ 32 ≈ 8.76 → round up to 9.)
How many square feet does a 4×8 sheet cover?: A 4×8 sheet covers 32 ft². In metric terms that’s about 2.97 m².
What waste factor should I use?: For simple rectangles, 10% is a common baseline. Increase waste for lots of cut-outs, angled edges, or complex layouts.
How do I estimate the cost of plywood?: Total cost = Sheets × Sheet area × Price per area. The calculator estimates the total area you’ll buy (whole sheets) and multiplies by your price.