Laminate flooring calculator

Why square footage is not the answer

A square-foot number is not something you can buy. 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.

What "spare" means here, and what the answer leaves out

Read the spare line carefully. It is everything you end up owning above the bare floor area, which means the allowance you added on purpose is sitting inside it. On a 12 × 12 room with 20 sq ft cartons it reads 16 sq ft, but about 14 of those are the 10% — they leave the stack as off-cuts and go in the skip. The genuinely useful leftover, flat unopened planks kept for a repair, is whatever survives the cutting. If you want a repair kit you can rely on, buy a carton past the answer rather than trusting that line.

The floor is one rectangle. There is no field for a closet, a doorway, a hearth or an L-shaped run, which is why the allowance has to carry them and why the help text pushes it to 15% on a floor broken up by openings. Adding several rooms together works for area but flatters the waste, because each room brings its own perimeter, its own first rip and its own last row.

Nothing here lays a plank. It cannot tell you how wide the final row comes out, whether the first row should be ripped narrower so the last one is not a sliver, or where the end joints stagger. That layout decides whether the floor reads as a floor, and it is worked out with a tape measure in the room, not with a percentage.

Underlayment is the bare floor area divided by the roll, with nothing added for overlap at the seams. If yours is laid with a lapped and taped edge, take the usable coverage off the roll's own instructions rather than the area on the label.