How this calculator works
Sheets = round up[(area x waste factor) / sheet area]. Default sheet is the common 4 x 8 ft panel (1.22 m x 2.44 m).
Worked example
A 4 m x 3 m subfloor (12 m2, 10% waste = 13.2 m2) with a standard 4x8 ft sheet (2.973 m2) needs 5 sheets.
Assumptions to check
- This estimates sheet quantity only. Span ratings, joist/stud spacing suitability, and load capacity are out of scope - a structural/code question, not a material-quantity one.
- The area is treated as a simple rectangle; openings and irregular cuts increase real-world waste beyond the default.
- Fixings and any required membrane/tape are not included.