HowMuch

Laminate flooring calculator

Enter the room and the square feet printed on your carton, and this gives you the number of boxes. Square footage alone will not do it — cartons of the same brand cover anywhere from 16 to 30 sq ft.

Cartons to buy 8 boxes Rounded up — you cannot buy part of a carton.
Floor area 144 sq ft
Area plus waste allowance 158.4 sq ft
Flooring you end up owning 160 sq ft
Spare left over 16 sq ft Keep it. You cannot match the colour later.
Underlayment rolls 2 rolls

Why square footage is not the answer

Every other laminate calculator hands back a square-foot number. You cannot buy square feet. Laminate is sold by the carton, and the coverage of a carton is not standard — Pergo's own project checklist tells you to "check each carton or ask a Pergo representative to determine the square footage of flooring included per carton. It can vary by style." In practice the range runs from about 16 sq ft for a thick 12 mm plank up to 30 sq ft for a thin, wide one.

So the same 144 sq ft room is 8 cartons at 20 sq ft each, but 6 at 26 sq ft. Look at the carton before you do the arithmetic — the number is on the end panel, usually to two decimal places.

The 10% is the manufacturer's own figure

Pergo's instructions are explicit: "Add a 10% waste factor to your total square footage to account for cutting, installation errors and variation in floor design." That last phrase matters — laminate is printed, and you will reject the occasional plank because its pattern lands next to an identical one. Go to 15% if you are laying diagonally, running a herringbone, or working around a lot of doorways and closets, where every opening produces an unusable off-cut.

Then the carton rounding lands on top. A 144 sq ft room needs 158 sq ft of flooring, which is 7.9 cartons at 20 sq ft, so you buy 8 and own 160. On a small room that rounding alone can be another 10%, which is why the answer here is cartons and not a percentage.

Buy the spare with the first order

Laminate is printed in production runs and the runs do not match. A carton bought three months later will be a slightly different colour and, more visibly, will repeat a different set of plank images. There is no way to blend it in.

Order the spare at the same time as the floor, keep it flat and dry, and you have a repair kit for the day a fridge wheel gouges a plank. Replacing one plank in a click-lock floor is a real job you can do; matching one is not.

Two things the calculator cannot do for you

Acclimation. Pergo requires unopened cartons to lie flat in the room for at least 48 hours before you start. Laminate expands and contracts with humidity, and a floor laid straight off a cold truck will buckle.

The expansion gap. A 3/8 in gap must be left all the way round the perimeter — against every wall, pipe, door jamb and hearth. It does not change the amount of flooring you buy, because you are still covering the same room, but it is the single most common cause of a floor that lifts in the middle. Skirting and quarter-round cover the gap; nothing covers a buckled floor.

Underlayment is a separate purchase unless the planks have a pad already attached — and if they do, do not add another. Two layers of foam make the click joints flex and eventually fail.

Common cases

Questions people ask

How many boxes of laminate flooring do I need for a 12x12 room?
8 cartons if yours cover 20 sq ft each. The room is 144 sq ft, Pergo's 10% waste allowance takes it to 158, and 158 ÷ 20 rounds up to 8. If your cartons cover 26 sq ft it is 7, and at 16 sq ft it is 10 — check the end of the box before you order.
How much extra laminate flooring should I buy?
10% is the figure in Pergo's own installation instructions, covering cuts, mistakes and planks you reject for pattern repetition. Raise it to 15% for diagonal or herringbone layouts and for floors broken up by closets and doorways. Then let it round up to whole cartons — on a small room the rounding often supplies the spare by itself.
Can I buy one more box later if I run out?
You can buy a box, but it will not match. Laminate is printed in runs, and both the colour and the set of plank images change between them. Buy the spare with the original order and store it flat — it is the only way to repair a damaged plank years later.
How big does the expansion gap need to be?
3/8 in around the entire perimeter, per Pergo's installation guide — against walls, pipes, door jambs and hearths. The floor floats and moves with humidity, and a gap that is pinched anywhere will push the floor up into a ridge somewhere else. Baseboard and quarter-round hide it.
Do I need underlayment?
Yes, unless the planks have a pad bonded to the back. It cushions, quietens and — on a concrete slab — carries the moisture barrier. If the pad is already attached, do not add a second layer; the extra give works the click joints loose.

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