Flooring Calculator
Square footage and boxes of flooring, with waste included.
10% for straight installs, 15% for diagonals, patterns, or complex rooms.
Printed on the box. Laminate and vinyl plank are commonly 18 to 24 sq ft.
You need
7 boxes
Covers 140.0 sq ft. Keep leftovers for future repairs.
- Floor area
- 120.0 sq ft
- Area including waste
- 132.0 sq ft
Estimates only. Verify quantities before ordering.
How this is calculated
Area = length x width. Total to buy = area x (1 + waste %). Boxes = total / coverage per box, rounded up to a whole box.
Enter the room's dimensions, a waste factor, and the coverage printed on the flooring box, and this calculator tells you the total square footage to buy and how many boxes that is. For L-shaped or multi-room projects, split the space into rectangles, calculate each, and add the areas before dividing by box coverage.
The waste factor covers cut ends, defective planks, and pattern matching. 10% is right for a straight lay in a simple room. Use 15% for diagonal installs, herringbone and other patterns, rooms with many corners and closets, or tile and plank products with strong repeating patterns.
Flooring for common room sizes
Rows assume a straight lay with 10% waste and boxes covering 20 sq ft, the common size for laminate and vinyl plank.
| Room size | Boxes | Sq ft with waste |
|---|---|---|
| 10 x 10 ft | 6 boxes | 110.0 sq ft |
| 12 x 10 ft (bedroom) | 7 boxes | 132.0 sq ft |
| 12 x 12 ft | 8 boxes | 158.4 sq ft |
| 15 x 12 ft (living room) | 10 boxes | 198.0 sq ft |
| 20 x 15 ft (great room) | 17 boxes | 330.0 sq ft |
| 12 x 24 ft (open plan) | 16 boxes | 316.8 sq ft |
Laminate, vinyl plank, engineered, or solid wood
Laminate is a photographic layer over a fiberboard core: inexpensive, hard-wearing against scratches, and vulnerable at the seams if water sits on it. Luxury vinyl plank has largely displaced it in wet-prone rooms because it is genuinely waterproof through its thickness, comfortable underfoot, and available in rigid core constructions that span minor subfloor imperfections.
Engineered wood is real wood veneer over a plywood core. It behaves far better than solid wood over concrete and in basements because the cross-laminated core resists the seasonal movement that makes solid wood cup and gap. Depending on wear-layer thickness it can be sanded once or twice; thin veneers cannot be refinished at all.
Solid hardwood remains the longest-lived option, refinishable many times over decades, and the most restricted in where it can go. It should not be installed below grade or directly over concrete without a proper subfloor and vapor management, and it needs a stable indoor climate year round to stay flat.
Acclimation and expansion gaps
Nearly all flooring needs to sit in the room where it will be installed, unboxed or loosely stacked, until it reaches the temperature and humidity it will live at. Wood products commonly want three to five days and sometimes longer; many rigid vinyl products need only 48 hours. Installing straight off the truck is the most common cause of gaps opening in winter or buckling in summer.
Every floating floor needs an expansion gap around its entire perimeter, typically a quarter to a half inch, hidden under baseboard or quarter round. The floor must be free to move as a single sheet. A single screw through a floating floor, a heavy island fixed on top of it, or trim nailed down through the planks pins it and produces buckling somewhere else in the room.
Large runs need intermediate expansion breaks. Most manufacturers specify a maximum continuous length and require a T-molding beyond it, and they require breaks at doorways between rooms. It is tempting to run one continuous floor through a whole house for looks, and doing so voids most warranties.
Subfloor prep and underlayment
Flatness is the requirement that decides whether a floor succeeds. Most manufacturers call for something like 3/16 inch over 10 feet. Rigid planks laid over a wavy subfloor either flex and creak or, worse, allow the click joints to work apart under foot traffic until the seams separate permanently. Check with a long straightedge and fill hollows with a levelling compound before starting rather than hoping the floor bridges them.
Underlayment does several jobs and the right one depends on the floor. Foam pads cushion and quiet a floating floor; some planks come with it pre-attached, in which case adding more is a mistake that makes the floor too soft and stresses the joints. Over concrete, a vapor retarder is essential regardless of the flooring, since slabs pass moisture continuously even when they feel dry.
Test concrete for moisture before buying anything. A simple plastic sheet taped down for 24 hours will show condensation if there is vapor drive, and calcium chloride or relative humidity probe tests give a number to compare against the flooring specification. Discovering a moisture problem after installation means removing the floor.
Common questions
How much extra flooring should I buy?
Add 10% for a standard straight installation and 15% for diagonal layouts, patterns like herringbone, or rooms with lots of jogs and closets. It also pays to keep one unopened box after the job: matching a discontinued floor years later for a repair is nearly impossible.
How do I measure an irregular room?
Break the floor plan into rectangles, including closets and doorway thresholds, and measure each one at its longest and widest points. Add the areas together, then apply the waste factor to the total. When in doubt, round each measurement up to the next half foot.
Why does box coverage vary so much?
Plank width and length differ by product, so a box of wide-plank vinyl might hold 28 sq ft while a narrow laminate holds 18. Always use the exact coverage printed on the specific product you are buying, and note that some brands print coverage before waste.
Does flooring really need to acclimate?
Most laminate and hardwood should sit in the room, boxed, for about 48 hours before installation so it adjusts to the room's temperature and humidity. Many modern rigid-core vinyl products (SPC) skip this requirement, but check the manufacturer's instructions, since skipping required acclimation can void the warranty.