A 16 × 14 ft living room and a 12 × 11 ft bedroom add up to 356 sq ft of floor. With the usual 10% for a straight lay that is 391.6 sq ft, which takes 20 cartons of luxury vinyl plank at 20.1 sq ft per carton. Measure each room wall to wall, add the waste allowance for your layout, divide by the coverage printed on the carton and round up.
How the flooring calculator works
Every room is length times width; the calculator adds the rooms together, so an L-shaped space is simply two rectangles. The waste allowance covers the offcuts at every wall and the planks you reject for color or damage. Cartons are the area with waste divided by what one carton covers, always rounded up to a whole box.
cartons = (sum of length × width) × (1 + waste %) ÷ sq ft per carton, rounded up
quarter round sticks = (room perimeters − doorway widths) × (1 + waste %) ÷ 8 ft, rounded up
Underlayment rolls are the floor area divided by 100 sq ft, the size of a common foam roll such as QuietWalk.
Worked example: two rooms of vinyl plank
- Living room: 16 ft × 14 ft = 224 sq ft. Bedroom: 12 ft × 11 ft = 132 sq ft. Total 356 sq ft.
- With 10% waste: 356 × 1.10 = 391.6 sq ft.
- LifeProof plank at 20.1 sq ft per case: 391.6 ÷ 20.1 = 19.5, so 20 cartons, 402 sq ft in the boxes.
- Quarter round: the two perimeters are 60 ft and 46 ft, 106 ft in all. Three 36 in doorways leave 97 ft of wall. With 10%, 106.7 ft, or 14 sticks of 8 ft.
- Two doorways where the new floor meets carpet or tile: 2 transition strips of 78¾ in.
- No underlayment: this plank has its pad attached.
The same two rooms in Pergo Outlast+ laminate (19.63 sq ft per case) also come to 20 cartons, plus 4 rolls of underlayment. In Bruce ¾ in solid oak at 20 sq ft per carton, a straight lay is 20 cartons and a diagonal lay at 15% is 409.4 sq ft, or 21 cartons.
How many boxes of flooring do I need for hardwood, vinyl plank or laminate?
Carton sizes are what change the answer, so the calculator fills in a real product for each type and lets you type the number from your own box label.
| Flooring type | Default product | Coverage per carton | Expansion gap at walls |
|---|---|---|---|
| Solid hardwood | Bruce ¾ × 2¼ in oak | 20 sq ft | ¾ in (NWFA: the board thickness) |
| Engineered hardwood | Bruce ⅜ × 5 in click | 22 sq ft | ⅜ in (NWFA: the board thickness) |
| Luxury vinyl plank | LifeProof 8.7 × 48 in | 20.1 sq ft | ¼ in (LifeProof) |
| Laminate | Pergo Outlast+ 7.48 × 47.24 in | 19.63 sq ft | ⅜ in (Pergo Outlast+) |
The expansion gaps come from the installation instructions: the NWFA Installation Guidelines say the gap at walls "generally is equal to the thickness of the material", LifeProof asks for ¼ in around the room and every fixed object, and Pergo Outlast+ asks for ⅜ in on all sides.
Waste for straight, diagonal and herringbone layouts
Pergo's Installation Essentials Guide and the LifeProof instructions give the same figures: add 10% for a standard installation and 15% for a diagonal one. Herringbone cuts every piece at the walls at 45°, and This Old House recommends at least 15% for it. Those are the defaults when you switch the layout; small rooms, closets and lots of doorways use more, a big open rectangle less.
Multiple rooms, hallways and closets
Add each space as its own room: a closet is a 3 × 2 ft room, a hallway a 12 × 3.5 ft room. Treating them separately keeps the perimeter right for the trim count. To split an odd floor plan into rectangles first, the room square footage calculator does it with L-shapes and cut-outs.
Floating floors need room to move. Pergo requires a T-molding across any floor longer or wider than 40 ft and at every doorway narrower than 4 ft; LifeProof sets its limit at 35 ft. The calculator warns you when a room passes 40 ft.
Quarter round, baseboard and transitions
Quarter round (or shoe molding) sits on the floor against the baseboard and hides the expansion gap. The calculator takes the room perimeters, subtracts your doorways and buys 8 ft sticks with the same waste allowance, because miters at inside corners eat length. If you are replacing the baseboard too, the baseboard calculator works out the pieces and corner cuts.
Every doorway where the new floor meets a different one gets a transition strip; the Pergo 4-in-1 molding is 78¾ in long, enough for one standard door.
What to do next
- Laying laminate or click vinyl? The laminate flooring calculator draws the rows and tells you whether to rip the first row so the last one is not a sliver.
- Bedrooms in carpet instead? The carpet calculator plans the cuts from a 12 or 15 ft roll.
- Kitchen or bath in tile? Use the tile calculator for tiles, grout and thinset.
- For the price with labor, removal of the old floor and subfloor work, run the flooring cost calculator.
All floor, tile and trim tools are listed on the floors, tile and trim page.