How to use this calculator
Put the room in as feet and the plank in as inches. Most laminate is 7 to 8 inches wide and 48 inches long, with cartons covering 18 to 22 square feet. Set the coverage from the label, not from memory: it changes between widths inside the same product line.
Leave the pattern on plank stagger. The plan will draw each row, randomise the starting length and show you which planks have to be cut. Check the stagger it draws against the minimum on your instruction sheet.
Expansion gaps change your numbers
Laminate is a floating floor over a fibreboard core, and that core moves with humidity. The gap at every vertical surface — walls, door jambs, pipes, the hearth, the island — is set by the manufacturer, not by a universal rule: Shaw’s instructions for its Repel laminate ask for 3/8 inch all round, including cabinets, pipes and toilet flanges. In a 12 by 14 room a 3/8 inch gap takes about 1.6 square feet off the finished floor, which is nothing on the order, but it changes the cut list on the first and last row.
What actually costs you material is the rip. If the room is 144 inches wide and the plank is 8 inches, the room is 18 planks exactly, and the last row would be a full plank with no gap — which is not allowed. So you rip the first row to about 7 1/2 inches and the last to about 7 3/4. Two long thin strips of waste, every time.
Long runs need a break in the floor too, and again the number is the manufacturer’s. Shaw’s Repel instructions recommend a T-moulding at doorways 36 inches or narrower that have a door and frame, and every 45 feet of length or width, and say elsewhere that one is only required in rooms over 2,025 square feet. Other brands set other limits. It is not a defect; it is how a floating floor survives a season.
AC ratings and thickness
The AC rating is an abrasion class. It comes from the European laminate standard, EN 13329, and runs from AC1 to AC6; the North American standard, NALFA LF-01, does not use it, although the label has become common in marketing here. Which class to buy is a judgement call, not a rule. This site’s suggestion is AC3 for a normal family home and AC4, at around 40 cents a square foot more, for a kitchen, an entry or anything you are renting out. The higher classes cost more again and add little in a house.
Thickness is 7, 8, 10 or 12 mm. Thicker planks feel more solid underfoot and bridge small subfloor imperfections better, but the AC class measures the surface, not the thickness. An 8 mm AC4 has the more abrasion-resistant surface of the two when set beside a 12 mm AC3.
The edge profile is the other thing to check on the sample before you order. A square edge reads as one continuous surface and hides a slightly uneven subfloor; a painted or embossed bevel reads as individual planks and collects dust in the groove. Neither is better, but they look completely different once a whole room is down, and a display board of six planks does not show it. Ask for a full plank to take home if you can.
Underlayment
If the plank has no attached pad you need underlayment, and you buy it in the same square footage as the floor plus about 5% for the overlaps at the seams. Over a concrete slab you need a vapour barrier under or built into the pad. For planks with an attached pad, Shaw’s Repel instructions call for 6-mil polyethylene sheeting over concrete, seams overlapped 6 to 8 inches and taped, and no extra plastic over a wood subfloor. Moisture rising out of a slab is the one thing a fibreboard core cannot take.
Do not double up. A second, soft pad under one that is already attached gives the click joints room to flex, so add one only if the instructions say you may.
If the floor is going above a bedroom or in an apartment, sound matters too. The number for footfall noise is the Impact Insulation Class, IIC, defined by ASTM E989, and it rates a whole floor-ceiling assembly, not a roll of underlay on its own. The International Building Code asks for at least IIC 50 between dwelling units when the assembly is tested in a laboratory. A building’s own rules can ask for more, so read the bylaws before you order the underlay.
Common mistakes
- Guessing the acclimation. Requirements differ: Shaw’s Repel laminate needs no acclimation period when the house is climate-controlled before and during the install, while other products ask for a set time in the room with the cartons flat and unopened. Read the sheet for yours and do what it says.
- Wet mopping. Read the warranty before you believe the box: Shaw’s care instructions for its own Repel line say it is water resistant but not waterproof. Water through a seam swells the core permanently. If the room has a floor drain or a toilet, consider vinyl plank instead — the trade-offs are laid out in LVP vs laminate.
- Nailing the transition strips through the floor. The floor has to float. Fasten the track to the subfloor in the gap, not through the plank.
- Pattern repeat. Cheap laminate has four or six printed faces and they repeat. Pull planks from three cartons at once or you will see the same knot four times in one row.
- Under-ordering the waste. The calculator starts a 48 inch plank at 13%, and that is the floor, not the ceiling — read flooring waste factor before you place the order.