EstimatorKitFree flooring calculator
Flooring by the carton, and how the rows land
Give a room and a product and this returns whole cartons of laminate, vinyl plank, engineered or solid flooring, the underlayment rolls under them and a transition stick for each doorway. It also lays the rows out: how many full ones fit across the run, how wide the strip against the far wall comes out, and whether that strip is too narrow to click in — the layout question that decides how a floor looks and that a square-footage total cannot answer.
- 100% free
- No signup
- 4 plank products
- Last-row rip check
- Underlayment and transitions
0.25 in expansion gap — the 1/4 in perimeter gap laminate installation sheets call for. Floats, so it needs underlayment and a transition past 40 ft of run.
Rows cross the run, so this is what decides the last-row rip. Nailed-down boards also have to cross the joists.
Whole boxes, because that is how it is sold
16 boxes
- Those boxes cover
- 320 sq ft
- Floor, bare
- 293 sq ft
- With 8% for cuts
- 317 sq ft
- Spare after the last row
- 3.2 sq ft
- Underlayment
- 3 rolls
- Transition sticks
- 2 × 78 in
How the rows come out
Across 13' 4" of room, less 0.5 in of expansion gap, you get 21 full rows and a final strip 2" wide.
That last strip is under 2 in, which is too narrow to hold a click joint or to sit flat. Rip the first row down as well and run both at 4 3/4" — the room looks balanced and neither edge is a sliver. Decide this before the first board goes down; it cannot be fixed at the far wall.
Each row takes 6 planks along 22', leaving 2' 1/2" at the end. That offcut is longer than the 8 in minimum stagger, so it starts the next row and nothing is thrown away.
The 8% allowance is on top of the bare 293 sq ft, not folded into it, so you can hold a quote against either figure. Boxes then round up once, at the end — which is why the spare comes out at 16% of a box rather than a convenient number.
How to work out how much flooring to order
Product, direction, then the row layout almost nobody checks before ordering.
Pick the product, then correct the carton figure
Laminate, vinyl plank, engineered and solid each arrive with a different plank size, a different expansion gap and a different run limit, so the choice sets four defaults at once. The square feet per box is the one that changes most between brands — 18 to 30 is the ordinary range — so read it off the end of the carton and type it in rather than trusting the prefill.
Say which way the planks run
Rows are laid across the run, so this choice decides which room dimension gets divided by the plank width and therefore how wide the final strip lands. It is also a structural question for nailed-down solid boards, which have to cross the joists rather than lie along them, and an aesthetic one for everything else: running the length of the room and away from the main window hides the seams.
Read the boxes, then check the last row before you start laying
The panel gives whole boxes, what they cover, the spare left over, the underlayment rolls and a transition stick per doorway. Under it sits the row layout: how many full rows fit and how wide the strip against the far wall comes out. If that strip is under 2 in the page says so and gives the width to rip both edge rows to instead, which is a decision that has to be made before the first plank goes down.
Technical specifications
| Products | Laminate, vinyl plank, engineered wood and solid hardwood, each with its own gap, stagger and run limit |
|---|---|
| Carton coverage prefills | 20 sq ft laminate, 24 vinyl plank, 23 engineered, 20 solid — all editable, the label wins |
| Waste allowance | 8% by default for plank goods, adjustable, shown next to the bare square footage |
| Expansion gaps applied | 1/4 in laminate and vinyl, 1/2 in floating engineered, 3/4 in solid — the board's own thickness |
| Last-row rule | Under 2 in the shortfall is split across the first and last rows and the balanced width is given |
| Run limits | 30 ft for click vinyl, 40 ft for laminate and floating engineered, none for nailed-down solid |
| Transition stock | 78 in and 94 in sticks, one uncut piece per opening, chosen by the widest doorway |
| Leaves the browser | Nothing. The four product rows ship inside the HTML, which is why the box count still appears in an empty house with no Wi-Fi |
Frequently asked questions
How many boxes of flooring do I need?
Divide the room area plus its waste allowance by the square feet in one carton, then round up once — and buy one carton beyond that. The reason for the extra is the run number stamped on the label: boards are milled and printed in batches, and a carton bought next year will differ enough in tone that a patched board reads as a patch. Cartons are not returnable once opened in most stores, so the spare costs the price of a box and saves the price of a floor.
Which direction should the planks run?
Along the longest dimension of the room and away from the main window, unless the floor is nailed down, in which case the joists decide. Solid boards fastened through the subfloor have to run perpendicular to the joists so each board is fixed at multiple points; laying them parallel means every board sits in a single bay and the floor moves with the subfloor. Floating floors have no such constraint, so the choice is about seams, which disappear when the plank length runs with the light rather than across it.
The last row comes out two inches wide — is that a problem?
Yes, and the fix is at the opposite wall. A strip under about 2 in has almost no tongue left to click into, snaps while you are levering it in and looks like a mistake even when it survives. Take the shortfall and split it across the first and last rows: if the leftover is 1.5 in and the plank is 7.5, rip both edge rows to 4.5 in and the room reads as deliberate. This has to be decided before the first row is laid, because the first row sets every row after it.
How big does the expansion gap have to be?
A quarter inch for laminate and rigid-core vinyl, half an inch for a floating engineered floor, and for solid hardwood a space equal to the thickness of the board — 3/4 in for a standard strip, which is the NWFA guideline. The gap is not a tolerance for bad cutting: a floating floor is one rigid panel the size of the room, and it grows and shrinks across its width with the season. Pinch it at a wall, a pipe or a door casing and it has nowhere to go but up, which is what peaking is.
How long a run can a floating floor go without a transition?
Around 30 ft for click vinyl and 40 ft for laminate and floating engineered, though the number that matters is the one in your own installation sheet, because exceeding it voids the warranty. Past that distance the accumulated seasonal movement is more than a perimeter gap can absorb, so the floor has to be broken into two independent fields with a T-molding — usually hidden in a doorway, occasionally in the middle of a long open-plan space, where it is the price of not having a floor that buckles.
Do I need underlayment under vinyl plank?
Only if the plank does not already have a pad attached, and doubling up is worse than none. An attached pad plus a foam roll gives the click joints too much to sink into; the locking edges work against each other every time somebody walks across, and they wear out. Where a separate roll is called for, the standard one covers 100 sq ft, comes as foam or as a 2-in-1 with a vapor barrier built in, and on a concrete slab the vapor barrier is not optional at any thickness.
How flat does the subfloor have to be first?
Most floating-floor sheets ask for 3/16 in in 10 ft, which is flatter than a lot of houses are. Lay a straightedge across the room in several directions before ordering anything — a dip the planks bridge becomes a hollow spot that clicks underfoot within a month, and a hump puts all the load on one row of joints. Leveling compound or a sanded-down high spot is far cheaper at this stage than after 40 boxes are down.
About buying flooring by the carton, and laying it out before you buy
Plank flooring is priced per square foot and sold per carton, and those two facts do not meet in the middle. A carton holds somewhere between 18 and 30 square feet depending on plank thickness and length, the figure is stamped on the carton and it differs for every product on the aisle, which is why a calculator that stops at “you need 312 square feet” has stopped one step early. The rounding should happen exactly once, against that carton figure, at the end: rounding the room up, then the waste up, then the cartons up compounds three cushions into a stack of boxes nobody asked for. What is worth an extra carton on purpose is the run number on the label, because flooring is printed and milled in batches and a board pulled from next year’s batch will not match the floor it is patching. Tile has the same problem under a different name and is counted a different way, piece by piece, on the tile calculator.
The part almost no flooring calculator touches is where the rows land. Take the room dimension across the run, subtract the expansion gap at both walls, divide by the plank width, and the fraction left over is the strip that will sit against the far wall for the life of the floor. If it comes out under about 2 in it is a problem, not a detail: there is not enough tongue left to lock, the piece flexes as you lever it home, and the eye reads it as a mistake. The fitter’s answer is to take the shortfall and share it — rip the first row down so the first and last rows are the same width — and it only works if the decision is made before the first board is laid. The end joints have their own rule running the other way: stagger them at least 6 in on narrow strip and 8 to 12 on wide plank, which is exactly why the offcut from the end of one row is usually the piece that starts the next, and why a room whose length divides evenly into the plank length wastes more than one that does not.
Everything above assumes the floor can move, and a floating floor is a single rigid panel the size of the room. That is where the gap comes from, it is why a click vinyl floor over about 30 ft of run and a laminate floor over about 40 need a T-molding to split them into two fields, and it is why the subfloor has to start flat — 3/16 in in 10 ft is the usual requirement, and it is flatter than most houses. Transition pieces come as uncut 78 in and 94 in sticks, one continuous piece per opening, because a spliced threshold in a doorway is the first thing to lift. Where the space underneath is a crawlspace or an unheated garage, the floor above it is also a thermal boundary and the insulation calculator covers the batts that go between the joists. If the room is getting broadloom instead, the arithmetic changes shape entirely — carpet is cut from a fixed-width roll rather than counted in boxes, and the carpet calculator works in seams instead of rows.
What this page does with your room
Every number on this page is worked out by JavaScript running in the tab you are reading it in. Nothing you type — measurements, quantities, the prices your supplier quoted you — is uploaded, logged or kept, which is also why the calculators carry on working on a site with no signal.
No retailer is told which product you selected or how big the room is. There is no cart behind this page and no way for one to be attached to it later without you noticing.