Flooring calculator

How it works

Formula: Boxes = area × (1 + margin/100) ÷ area per box

The room area (length × width) is increased by the margin, which covers the cuts along the walls and damaged planks. That area is divided by the area of one box, printed on the package, then rounded up to a whole box. The right margin depends on the room and the layout: you choose it.

Worked examples

• A 15 × 12 ft room, 20 sq ft boxes, 10% margin

  198 sq ft to buy: 10 boxes, with 20 sq ft left over.

• The same room with a 15% margin

  207 sq ft: 11 boxes.

• Boxes of 22.5 sq ft for 180 sq ft, 10% margin

  9 boxes, or 202.5 sq ft of planks.

Common mistakes

• Buying just the room's area.

  Cuts make offcuts: with no margin you would count 9 boxes instead of 10.

• Rounding the boxes down: 8 boxes.

  An opened box is bought whole: 9.

• Forgetting a closet or a hallway.

  Measure each part separately and add the areas.

What the calculation leaves out

• A rectangular room: for an L shape, split it into rectangles and add the areas.
• Underlayment, baseboards and transition strips are not counted.

Boxes of 20 ft² with a 10% margin

Frequently asked questions