How much flooring do I need?

The arithmetic, written out

Pergo prints this calculation as three boxes in its own project planner, and every honest flooring estimate on earth is those three boxes in some order. Length times width gives the room. The room times 1.10 gives the total you actually have to buy. That total divided by the square feet in one carton, rounded up, gives cartons. Notice that Pergo leaves the divisor blank on purpose and footnotes it: check each carton, because it varies by style.

Run it on the room this page opens with. Twelve by ten is 120 square feet. Times 1.10 is 132. At 20 square feet per carton that is 6.6 cartons, and no store sells six tenths of a box, so it is 7 cartons and 140 square feet arriving at your door. You paid for 140 to cover 120. The extra 20 is not somebody padding your order. It is the box size, and it belongs to you when the job is done.

How much of the waste is technical, and how much is somebody's margin

Ten percent is the figure Pergo publishes for laminate. It pays for the cuts at the walls, for the plank you snap on the wrong side of the pencil line, and for boards that come out of the carton with a flaw you would not accept in the middle of a room. For hardwood the same document says fifteen percent and cites NWFA. Those two numbers are the entire published universe on this page.

Nobody publishes a percentage for a diagonal lay, for herringbone, for a room shaped like an L, or for a floor that runs through four doorways, and the honest reason is that it depends on your plank length against your wall length in a way no single percentage can hold. So treat it this way: ten is technical, fifteen is technical for hardwood, and everything above that is a judgment call. A judgment call is something a person makes out loud, in front of you, with a reason attached. When it arrives silently, already folded into a carton count, it has stopped being a waste factor.

The point where the number you were given stops adding up

Here is the test, and it takes twenty seconds at a counter. Take the carton count somebody handed you. Multiply it by the square feet printed on that carton. Divide by your room's square footage. You now have the waste factor that person actually used, whether they told you or not.

Nine cartons at 20 square feet is 180 square feet. For a 120 square foot room that is 1.50, a fifty percent waste factor, against a published ten. One honest thing has to be said in the other direction: on a small room the rounding up to a whole carton is itself worth several percent, and that part is nobody's fault. So compare before the rounding. If the implied factor sits near 1.10 for laminate or 1.15 for hardwood plus one carton of rounding, the number is fine. If it sits at 1.3 or 1.5 with no diagonal, no herringbone and no stairs in the conversation, ask what the extra is for and write the answer down.

The same square foot, sold to you three different ways

The shelf tag is per square foot. The register is per carton. A special order is per pallet. They are three prices for one floor and they are not interchangeable, which is exactly why comparing two stores on the shelf tag alone tells you very little.

Convert everything to the carton first, because the carton is the smallest thing you are allowed to buy. Shelf price per square foot times square feet per carton gives price per carton. Then do the number that matters and almost nobody does: multiply your rounded carton count by the price per carton, and divide by your actual room square footage. That is your real cost per square foot, and it is always higher than the tag. On the 120 square foot room above, 7 cartons cover 140, so your real cost per square foot is about seventeen percent above the tag before anybody has been dishonest with you.

The pallet is the one place a genuine break can exist, and no manufacturer publishes what it is. There is no public document to cite, so this page will not invent one. What you can do is ask the question in the form that gets an answer: how many cartons is a full pallet of this line, and what is the price per carton at that quantity. Two rooms of the same floor sometimes cross that line. One room almost never does.

The lines Pergo prints that most estimates never reach

The planner does not stop at cartons. It has four more steps, and its own cost worksheet has printed rows for wall base, quarter round, stair nose, a 4-in-1 kit, T-molding, a reducer, and underlayment or moisture barrier. Those rows exist because the manufacturer knows the floor alone does not finish a room.

• Underlayment. Total square feet divided by the square feet per roll, and the planner's own printed example uses 100 per roll. It also says plainly that if the floor you picked does not have underlayment attached, you need to buy one. Read your carton. If the pad is attached and it appears on your bill anyway, you are being sold the same layer twice.
• Vapor barrier. Installing over concrete requires one, in the planner's own words. That is a subfloor question, not a flooring question, and it does not show up in any square footage calculation.
• Wall base or quarter round. Add length and width, multiply by two for the perimeter, then subtract the total width of your doorways. On the twelve by ten room that is 44 feet of perimeter, less a three foot doorway, so 41 feet.
• Transitions. Pergo gives two options and two divisors: doorway widths divided by 6.56 feet for 4-in-1 kits, or divided by 7.87 feet for individual transition sticks. Round up, and the planner recommends an extra piece for cutting errors.
• Stair nose. Stair width times the number of stairs, divided by the molding length per piece. If your job has stairs, this line is frequently larger than people expect and it is priced per piece, not per square foot.

Pergo also prints a tool list next to all of this: tapping block and 5 mm spacers, moisture meter, circular saw, knee pads, felt furniture pads. None of that is material and all of it is money, and it is the reason a floor that looked cheap on the shelf tag lands somewhere else at the register.

Where the price range on this page comes from

Every figure above comes from one public document, named, linked and dated in the sources below, and you can open it yourself. The dollar range obeys the same rule, and for a long time this page said it could not, so here is exactly how it is done.

Sutherlands is a home improvement and lumber chain out of Kansas City, Missouri. Its product pages are unusual in one specific way: each one publishes a price for every one of its stores rather than a single national number. That means one public page states a low and a high on the same day, and the spread between the cheapest store and the dearest is a range somebody can check rather than a figure somebody asserted. These are the pages this calculator was read off, on 2026-08-23:

• LEN-DAL Chisholm Rugged Classic luxury vinyl plank, 7 by 48 inch, 19.02 sq ft per carton, item 3206562: 37.99 to 49.99 dollars across the 16 stores with it in stock. Open the product page.
• Shaw Cadence Versalock laminate, 7-1/2 by 54-1/2 inch, 10 pieces per carton, item 1992569: 56.99 dollars at the 1 store with it in stock. Open the product page.
• MP Global QuietWalk laminate floor underlayment, 100 sq ft roll, item 7954357: 39.99 to 48.99 dollars across the 3 stores with it in stock. Open the product page.

Now the limits, because a range with no limits printed next to it is worse than no range at all. This is one chain on one day. It is not a national average and it does not claim to be one. Retail flooring moves by region, by store, by week and by promotion, and a designer line and a builder line sell the same square foot at very different money. So the tag in front of you outranks all of it: type that number into the price field and every figure on this page redoes itself on yours, and the reading above steps aside.

Pergo's own planner ends with a blank cost worksheet, and the manufacturer would not fill it in either. It closes by saying the planner is a guide and cannot guarantee the figures will satisfy the needs of your installation. That sentence belongs on every calculator on the internet, including this one. The difference between a blank field and a cited range is not honesty, it is how much work the page did before handing you the pen.

Sources for everything above: Pergo (Mohawk), Wood and Laminate Flooring Project Planner, mohawk.blob.core.windows.net/pergo/pdfs/Pergo_Project_Checklist.pdf, opened 2026-08-23, for the waste factors and the carton method. Sutherlands, the three product pages linked above, read 2026-08-23, for every dollar figure.