Sheathing Calculator
Convert an area into sheet counts with editable panel dimensions and waste.
Use the active project roof area or a manual area entry to estimate sheathing purchase counts.
Material ListArea source
Use the roof calculator's active project area or override it manually.
Chained roof area
Run the roof calculator first to prefill sheathing with the active project roof area.
Panel setup
Set panel size, waste, and what this sheathing is going on.
You'll need 52 sheathing panels for 1,500 sq ft.
You'll need
Sheathing estimate
Warnings
- INFO No roof area is saved in the active project yet, so the manual area is being used.
Detail values
- Area used
- 1,500 sq ft
- Sheet area
- 32 sq ft
- Base sheets
- 46.88
Assumptions
- Default panel size: 4 ft x 8 ft when unchanged
- Sheathing spec: 0.4375" OSB for roof sheathing (editable; not a code minimum — verify local requirements)
Included: sheathing panels, waste allowance.
Not included: labor, delivery, permits, disposal of waste material.
Formula details
- Sheet area: sheetWidth x sheetLength
- Base sheets: area / sheetArea
- Purchase sheets: ceil(baseSheets x (1 + wastePercent))
FAQ
Can I change the panel size from 4x8?
Yes. Both sheet width and length are editable so you can match the product you plan to buy.
Does this only work for roofs?
No. It works for any surface area as long as you enter the correct square footage.
Why is the purchase count rounded up?
Sheets are sold whole, so the calculator rounds up after the waste factor is applied.
What do Context and Material change?
Only the default thickness suggestion and the spec shown in the assumptions list — they don't affect the sheet count, which is driven purely by area and sheet size. Set them to document what you actually plan to buy.