Plywood calculator

32 sq ft on a 4×8 sheet.

Cuts. A simple rectangle can be under 10. Hips and valleys on a roof run higher.

Job sheet

Plumb plywood job sheet

32 sq ft sheets.

  • Sheets22704 sq ft after allowance.
Plumb plywood job sheet
32 sq ft sheets.

Sheets: 22 (704 sq ft after allowance.)

Divide the area by 32 and round up, then add the cut allowance if you put it in the box. The allowance is applied before the round-up. Board feet of the joists under the sheet are not on this page. That is board feet. Roof area after pitch is roofing. Studs behind wall sheathing are studs.

FAQ

How many 4×8 sheets?

A 4×8 sheet is 32 square feet. 640 square feet is 20 sheets exactly. Ten percent for cuts is 22 sheets. A 4×10 is 40 square feet. Change the sheet size.

OSB or plywood?

Same count. The sheet still covers 32 square feet if it is 4 by 8. The span rating on the stamp is a different question. This page does not pick a thickness.

Sources

  1. NIST PS 20 and ordinary sheet goods: A 4 by 8 foot sheet is 32 square feet by the definition of the foot. OSB is sold in that same rectangle.