How much flooring do you need?

How much flooring do I need?

Measure each room, multiply length by width and add the rooms together, then add 10% for cuts. A 12 by 15 ft room is 180 square feet; with 10% extra that is 198 square feet. With boxes that cover 20 square feet each, you need 198 ÷ 20 = 9.9, so 10 boxes.

How many boxes of flooring do I need for 1,000 square feet?

Add the extra first: 1,000 square feet plus 10% is 1,100. Then divide by the coverage printed on the box. With boxes of 22 square feet, 1,100 ÷ 22 = 50 boxes. Always round up to a whole box.

How much extra flooring should I buy?

About 10% for planks laid straight in a simple room, 15% for a diagonal layout or a room with many corners, closets and doorways, and 15–20% for herringbone. A spare unopened box is handy for repairs later.

Is it the same for vinyl plank, laminate and hardwood?

Yes — you need the same floor area with the same extra; only the coverage per box differs, so read it off the box or the product page. Floating floors such as laminate and many vinyl planks go over an underlayment unless it is already attached to the planks; nailed-down hardwood does not float.

Should I include closets?

Yes. Include closets and any spot the floor runs under, such as a freestanding range or a refrigerator. Leave out the area under built-in cabinets and islands.

Why round up to a whole box?

Flooring is sold by the box and boxes usually cannot be split. In the example below you need 407.0 square feet with 10% extra, and a box covers 23.6 square feet, so 17.25 boxes means 18 boxes. The 17.8 square feet left over is a useful spare for later repairs. Buy all the boxes in one order, so that they come from the same production lot; color and finish can differ between lots.

Do I measure the room or the walls?

Measure the floor from wall to wall, including the space that will end up under baseboard and door casings. Rectangular rooms are length × width. For an L-shaped or irregular room, split it into rectangles, calculate each and add them. Subtract only large areas that will not be floored, such as a built-in island or a fireplace hearth.

The arithmetic

The floor area is the sum of the room areas in square feet. The extra for cuts and waste is added as a percentage, and the total is divided by the coverage of one box, rounded up. The percentage depends on the layout: it is lowest for planks laid straight in a simple room and highest for diagonal and herringbone patterns, where many ends are cut at an angle. Planks that are cut at the end of a row can often be used to start the next row, which is why the waste in a long, open room is lower than in a room with many corners.

Worked example: three spaces and 23.6 square foot boxes

A living room of 14 × 18 ft is 252 square feet, a 4 × 22 ft hall 88 and a 5 × 6 ft closet 30, 370 square feet in all. With 10% extra the total is 407.0 square feet, which is 18 boxes of 23.6 square feet, covering 424.8 square feet. With 15% extra for a diagonal layout, the total is 425.5 square feet and the count 19 boxes.

Common mistakes

Ordering exactly the floor area with no extra is the first mistake and leaves you short at the last row. The second is working from the nominal coverage on a different product than the one you buy; read the square feet per box on the box you will actually use. The third is forgetting underlayment, transitions, trim and the expansion gap that floating floors need at the walls, which your product's installation guide specifies. Wood and laminate floors are usually left in the room for a time before installation so they match its temperature and humidity; again, follow the manufacturer's instructions.

Sources: waste factors are common installer allowances, not a standard; the product's installation guide and the box coverage figures control. Related: laminate flooring calculator, tile calculator, carpet calculator and square footage calculator.