Flooring Calculator
This free flooring calculator turns your room measurements into the boxes of LVP, laminate or hardwood to buy, or the square yards of carpet, with waste for your layout pattern. It also counts underlayment rolls and trim pieces and gives you a cost. Add as many rooms as you need and leave out islands or closets.
Laying tile instead? Use the Tile Calculator for tiles, thinset and grout.
What this calculator does
It works out how much flooring a room or a whole floor needs, and what goes with it: underlayment or carpet pad, and quarter-round trim to cover the expansion gap at the walls. You get a shopping list to take to the store and a cost for doing it yourself versus having it installed. Prices are typical retail ranges unless you enter your own.
How it's calculated
- Floor area: each room's length × width, added up, minus any areas you leave out.
- Area to buy: floor area × (1 + waste). Waste is 10% for a straight layout, 15% for diagonal and 20% for herringbone or chevron, and 10% for carpet. You can set your own, from 0 to 30%.
- Boxes: area to buy ÷ the sq ft per box on the label, rounded up. Carpet: area to buy ÷ 9, in square yards.
- Underlayment: floor area × 1.05 for seams ÷ the roll's coverage (100 sq ft by default), rounded up. Carpet pad is counted in square yards.
- Trim: (the rooms' perimeter − doorways × 3 ft) × 1.10 for miters ÷ the piece length (8 ft by default), rounded up.
- Cost: each line's quantity × its unit price, added up. Installed cost adds a typical labor rate per sq ft for the flooring type.
Worked example
A 12 × 15 ft living room in LVP, laid straight, with one doorway. The floor is 180 sq ft; with 10% waste that's 198 sq ft to buy. The planks come 20 sq ft to a box, so 198 ÷ 20 = 9.9, rounded up to 10 boxes. Underlayment: 180 × 1.05 ÷ 100 = 1.9, so 2 rolls. Trim: the perimeter is 54 ft, less 3 ft for the doorway is 51 ft, plus 10% is 56.1 ft, or 8 pieces of 8 ft quarter-round. Expect about $498–$1,242 in materials, or $768–$1,962 installed.
Frequently asked questions
How much extra flooring should I buy?
Buy about 10% more than the floor area for a straight layout, 15% for a diagonal layout and 20% for herringbone or chevron. The extra covers cuts at the walls, damaged pieces and a few spare planks for repairs later. A 12 x 15 ft room (180 sq ft) laid straight needs 198 sq ft.
How many boxes of flooring do I need for a 12x12 room?
A 12 x 12 ft room is 144 sq ft. Add 10% for a straight layout to get 158.4 sq ft, then divide by the coverage printed on the box and round up. At 20 sq ft per box that is 7.9, so 8 boxes; at 23.6 sq ft per box it is 6.7, so 7 boxes.
Do I need underlayment for LVP?
Not if the planks have a pad attached, which many LVP products do; adding foam under an attached pad can void the warranty. LVP without a pad usually needs a thin underlayment, and over concrete you may also need a vapor barrier. Check the installation guide for your product.
How do I measure an L-shaped room?
Split it into two rectangles, measure each one wall to wall, and add the areas together. In this calculator, enter each rectangle as its own room row. Leave out anything that won't get the new floor, such as a kitchen island, as an area to leave out.
How much does it cost to install flooring?
Materials typically run $2 to $5 per sq ft for LVP, $1.50 to $4 for laminate, $4 to $10 for hardwood and $1.50 to $4.50 for carpet. Professional installation adds roughly $1.50 to $4 per sq ft for LVP or laminate, $3 to $8 for hardwood and $0.75 to $2 for carpet. A 12 x 15 ft room of LVP is about $500 to $1,240 in materials, or $770 to $1,960 installed.
Limitations
This is an estimate for rectangular areas. Box coverage varies a lot between products, so always use the figure on the label of the flooring you buy. Carpet is cut from fixed-width rolls, and the seam layout (which this tool doesn't plan) can add 10–20% over the area figure, so your installer's measure is final. Transition strips, stair nosing, adhesive, nails, moisture barrier, subfloor repair and removing the old floor aren't included. If the subfloor needs replacing, the Concrete Slab Calculator covers a new slab, and if you're finishing the whole room, the Drywall Calculator covers the walls and ceiling.
Put this calculator on your site
Run a blog or business site for DIYers, homeowners or contractors? You can embed the Flooring Calculator as a free widget — responsive, no registration, and no ads or tracking added to your page.
Cite this calculator
Using this tool in a class, a paper or an article? Copy a ready-made reference: