Calculator — Flooring & Tile
Laminate Flooring Calculator
Boxes of laminate flooring for any room — from box coverage and the 10% waste allowance installers use.
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About this calculator
Laminate is sold by the box, and you cannot buy a fraction of one. This calculator turns room area plus a waste allowance into a whole-box count, using the coverage figure printed on your exact product box.
What this number means
Laminate is sold by the box, and the box is the unit that decides the order — you cannot buy a fraction of one. The maths is simple on purpose: room area, plus a waste allowance for the cuts every install produces, divided by the coverage printed on the box, rounded up. The waste allowance is where installs go wrong: a straight lay wastes about 10%, a diagonal lay closer to 15%, and a room full of doorways and angles wastes more than a clean rectangle of the same size.
Two things buyers forget: underlayment and expansion. Most laminate needs separate underlayment (some planks carry it pre-attached — check the box), and every install needs a 3/8 in expansion gap at the walls, which the baseboard covers. Neither changes the box count, but both belong on the shopping list.
The formula
- Area = Length × Width
- Area with waste = Area × (1 + waste %)
- Boxes = Area with waste ÷ coverage per box, rounded up
- Square yards = Area ÷ 9 (for underlayment sold by the yard)
Worked example
A 15 × 12 ft bedroom, boxes covering 20 sq ft, 10% waste.
- Area = 15 × 12 = 180 sq ft (20 sq yd)
- With waste: 180 × 1.10 = 198 sq ft to buy for
- Boxes: 198 ÷ 20 = 9.9 → 10 boxes
Assumptions and limitations
- One rectangular room per calculation. For L-shaped rooms, total the rectangles first and run the total area.
- Coverage per box is the manufacturer's net figure for your exact product — boxes vary from about 15 to 25 sq ft, so do not guess it.
- Waste 10% covers a straight lay in a normal room; diagonal lays and rooms with many doorways want 15%.
- Closets, fixed cabinets and islands inside the measured rectangle should be deducted from the area first.
- Underlayment, transition strips and baseboard are separate purchases and are not counted here.
Frequently asked questions
At 10% waste you buy for 220 sq ft. With 20 sq ft boxes that is exactly 11 boxes. With 22 sq ft boxes it is 10 boxes — the box coverage figure decides the count, so use the number printed on your product.
Ten percent for a straight lay in a normal room. Fifteen percent for a diagonal lay, herringbone-style patterns, or rooms with many doorways, angles and closets that force extra cuts.
Typically 15–25 sq ft, most commonly around 20 sq ft. The exact figure is printed on the box and varies by plank size and planks per box — always use your product figure, not a generic one.
Usually yes, unless your planks carry pre-attached underlayment. Underlayment smooths minor subfloor unevenness, muffles sound and provides a moisture barrier on concrete. Buy it by the same square footage as the flooring, plus a little overlap.
Standard laminate swells with standing water, so it is a poor choice for full bathrooms. Water-resistant laminate works in kitchens if spills are wiped promptly and edges are sealed — check the product rating, not just the marketing name.
Split it into two rectangles, work out each area, and add them. Run the total area through the calculator — the box count comes out the same as measuring the whole shape at once, provided you deduct closets and fixed cabinets.