Flooring Box Calculator
Work out how many boxes of laminate, tile, or vinyl plank to buy. Enter room length and width, choose your install pattern to set the waste factor, add the coverage per box, and include extra boxes for attic stock so you never run short or mismatch a dye lot.
Last updated: May 2026
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About this calculator
This calculator turns a room's footprint into the number of flooring boxes to order. The formula is: Boxes = ⌈ (Length × Width × (1 + Waste ÷ 100)) ÷ CoveragePerBox ⌉ + AtticStock. Length times width gives the floor area in square feet. The waste multiplier (1 + Waste ÷ 100) adds material for the cuts made at walls, corners, and obstacles, and that figure depends heavily on the install pattern — straight runs waste about 8%, diagonal layouts 12–15%, and herringbone up to 20%. Dividing the adjusted area by the coverage printed on each carton, then rounding up, gives the number of full boxes the room needs. Finally, attic stock adds a few spare boxes set aside for future repairs: because flooring is made in dye lots and batch runs that change over time, a board replaced years later from a new lot rarely matches, so keeping sealed spares from the original purchase is the only reliable fix.
How to use
Suppose you are laying laminate in a 20 ft × 15 ft living room on a diagonal-tile pattern (15% waste), each box covers 22 ft², and you want 1 spare box of attic stock. Step 1 — Floor area: 20 × 15 = 300 ft². Step 2 — Add waste: 300 × (1 + 15 ÷ 100) = 300 × 1.15 = 345 ft². Step 3 — Divide by box coverage: 345 ÷ 22 = 15.7 boxes. Step 4 — Round up: 16 boxes. Step 5 — Add attic stock: 16 + 1 = 17 boxes to purchase. A simple straight layout (8% waste) would instead need 16 boxes total.
Frequently asked questions
How many boxes of laminate flooring do I need for a 20x15 room?
A 20 ft × 15 ft room is 300 square feet. With a typical diagonal-pattern waste factor of 15%, you need about 345 square feet of material. If each box covers 22 square feet, that is 15.7 boxes, which rounds up to 16, plus a spare box for future repairs gives 17 boxes. Always round up to whole boxes and keep at least one sealed spare, since matching a future board to the original dye lot is usually impossible once that batch sells out.
How much extra flooring should I buy for waste?
Plan for 8–10% extra on simple straight-lay installations, 12–15% for diagonal layouts, and up to 20% for herringbone or complex patterns. The waste comes from the partial planks and tiles cut to fit at walls, around door frames, and against cabinets and fixtures. Rooms with many corners, alcoves, or angled walls fall at the higher end. This calculator lets you pick the pattern so the waste percentage matches your real install rather than a generic guess.
What is attic stock and why should I buy spare flooring boxes?
Attic stock is the extra, sealed boxes of flooring you set aside after installation for future repairs. It matters because flooring is produced in dye lots and batches whose color, finish, and even thickness drift slightly between production runs. If a plank is later damaged by water or a dropped object, a board pulled from your original attic stock blends in perfectly, while a freshly bought box from a new lot almost never matches. One or two spare boxes is cheap insurance against an obvious repair patch.