Laminate flooring calculator

How this calculator works

It multiplies length by width, adds any closets or extra area, and adds a waste allowance for end cuts and the last row. Then it divides by the coverage printed on the box and rounds up to whole boxes, because stores do not sell partial boxes.

Underlayment is figured the same way from the roll coverage. Each doorway gets one transition strip, and a pack of spacer wedges holds the expansion gap while you work.

Worked example

A 16′ × 13′ living room is 208 sq ft of floor. With 10% waste you need 228.8 sq ft, which at 20 sq ft per box is 11.44 boxes, so the list buys 12 boxes (240 sq ft). The same 228.8 sq ft takes 3 rolls of 100 sq ft underlayment, plus one transition strip for the doorway and a pack of spacers.

Tips before you buy

• Let the unopened boxes sit in the room for 48 hours, or as long as the maker says, so the planks adjust to the temperature and humidity.
• Leave the expansion gap the instructions call for, usually about ¼″, at every wall and fixed object. Baseboard or quarter round covers it.
• Open and mix planks from three or four boxes as you go so color and pattern repeats spread out across the floor.
• Keep one unopened box for future repairs. Laminate patterns are discontinued often and a later batch may not match.

Questions

How much extra laminate should I buy?

Plan on 10% extra for a straight lay in a regular room. Diagonal layouts, rooms with many corners and very long planks waste more, so use 15% for those. The waste allowance is under Coverage and waste.

How many square feet are in a box of laminate?

Most boxes hold between 15 and 25 square feet, depending on plank size and thickness. Thicker planks usually mean fewer square feet per box. The number is printed on the label, so enter it rather than relying on the default.

Do I need underlayment under laminate?

Yes, unless the planks come with a pad already attached. Underlayment smooths small subfloor bumps, reduces hollow sound and, on concrete, needs a vapor barrier either built in or laid separately. Follow the flooring maker’s instructions, as the wrong pad can void the warranty.

Should I measure in square feet or by the plank?

Square feet. Laminate is sold by the box and labeled by coverage, so floor area plus waste divided by box coverage is all you need. Plank counts only matter for layout, not for buying.