How the calculator works
Flooring is sold by the box, and the only number that matters is the coverage printed on it. Boxes = (area × (1 + waste)) ÷ box coverage, rounded up. Waste covers end cuts (the offcut from the last plank in a row often can't start the next), defective planks, and the ripped final row.
Worked example: 350 sq ft of living room in planks boxed at 20 sq ft: 350 × 1.08 = 378 sq ft → 19 boxes, with about 2 sq ft to spare, which is why you round up, never down.
Setting the waste factor
- 8%: normal rectangular rooms, straight lay.
- 12%: diagonal installs, herringbone LVP, or many small rooms/hallways where every run ends in a cut.
- 5%: one big open rectangle and an experienced installer. Never below 5: one box of a discontinued color is an expensive hunt.
Underlayment and prep
- Many vinyl planks come with attached pad, and adding foam under those voids most warranties. Check the box.
- Laminate over concrete needs a vapor barrier (often built into combo underlayment).
- Flatness spec is typically 3/16″ over 10 ft. Fix dips with patch compound first; floating floors bounce and click apart over voids.
- Let boxes acclimate in the room 48 hours before installing, because planks move with temperature and humidity.