Calculator
Know how many boxes before you order.
Enter the room, choose a waste allowance and the box coverage. We round up to whole boxes so you do not come up short on the last row.
To work out how many boxes of flooring you need, multiply the room's length by its width in feet, add a waste allowance, then divide by the sq ft per box and round up to a whole box. Sq ft per box is listed on every product page under Coverage area. A 10 x 10 ft room is 100 sq ft. Add 10 percent and you need 110 sq ft. With boxes that cover 15.5 sq ft, 110 / 15.5 = 7.1, so you order 8 boxes. The calculator below does the same sum and rounds up for you.
You need
0 boxes
Covers 0 sq ft for a 0 sq ft floor, with 0 sq ft extra.
Based on 15.5 sq ft per box.
Waste allowance
How much extra should I order for cuts and waste?
Order 10 percent more than the room measures for a straight lay in a plain room, 15 percent for diagonal, herringbone or large format tile, and 20 percent for a room with lots of cuts and corners. If you are not sure, order 15 percent more. That covers cuts, breakages and the odd bad piece, and it keeps you on the safe side. Keep the offcuts, because they are the easiest repair you will ever have.
The formula
Boxes = (length in ft x width in ft) x (1 + waste allowance) / sq ft per box, rounded up to the next whole box.
Use the coverage on the box, not the tile size. Coverage per box is set by the maker and can come in a little under pieces times the nominal tile size.
Worked example: a 12 x 14 ft kitchen
The room is 12 x 14 = 168 sq ft. Laid straight, add 10 percent: 168 x 1.10 = 184.8 sq ft. The porcelain you picked covers 15.5 sq ft a box, so 184.8 / 15.5 = 11.92, which rounds up to 12 boxes. Twelve boxes cover 186 sq ft.
Laid on the diagonal, use 15 percent instead: 168 x 1.15 = 193.2 sq ft, and 193.2 / 15.5 = 12.47, so 13 boxes. The layout costs you one extra box here.
To price it, multiply the boxes by the box price. The box price is the price per sq ft times the sq ft per box, which is why both are shown on the product page.
Boxes by room size, with 10 percent extra
| Room (ft) | Floor area | With 10% extra | 10 sq ft box | 15.5 sq ft box | 22.38 sq ft box |
|---|---|---|---|---|---|
| 10 x 10 | 100 sq ft | 110 sq ft | 11 boxes | 8 boxes | 5 boxes |
| 10 x 12 | 120 sq ft | 132 sq ft | 14 boxes | 9 boxes | 6 boxes |
| 12 x 12 | 144 sq ft | 158.4 sq ft | 16 boxes | 11 boxes | 8 boxes |
| 12 x 14 | 168 sq ft | 184.8 sq ft | 19 boxes | 12 boxes | 9 boxes |
| 15 x 20 | 300 sq ft | 330 sq ft | 33 boxes | 22 boxes | 15 boxes |
Check the sq ft per box on the product you are buying before you order. If your box size is not in the table, the calculator above takes any figure.
How many 12x12 tiles do I need for a 10x10 room?
About 110 tiles. A 10 x 10 ft room is 100 sq ft, and a 12 x 12 in tile is 1 sq ft, so the room takes 100 tiles before waste and 110 with 10 percent extra. In boxes, that depends on the product: at 10 pieces a box it is 11 boxes. Pieces per box are listed on each product page.
How many 12x24 tiles come in a box?
There is no standard number. The maker sets the box count, and it changes between ranges even at the same size. One 12 x 24 in tile we sell comes 8 pieces to a box, listed at 15.5 sq ft. Eight tiles at 2 sq ft each add up to 16 sq ft, a little over the listed 15.5, which is why you should order by the listed coverage. Pieces per box and sq ft per box are in the spec table on every product page.
How much does a box of 12x12 tile cover?
It depends on the product, so read the Coverage area line on the product page. A box of 10 pieces at 12 x 12 in is listed at 10 sq ft on our site, but other ranges pack differently.
How do I calculate square footage for tile?
Measure the length and width of the floor in feet and multiply them. Convert inches to feet by dividing by 12, so 10 ft 6 in is 10.5 ft. Measure closets and alcoves as their own rectangles and add them on.
For an L-shaped room, split the floor into two rectangles that do not overlap, work out each one, and add them. For example, a 12 x 10 ft section (120 sq ft) plus an 8 x 5 ft section (40 sq ft) is 160 sq ft. Add 10 percent and you need 176 sq ft. At 15.5 sq ft a box, 176 / 15.5 = 11.35, so 12 boxes.
More calculators
Laying tile? Try the tile calculator. Laying planks? Try the laminate and vinyl plank calculator.