Tile Calculator

How to calculate how many tiles you need

1. Find the area to tile. Multiply the length by the width. For a room with more than one section, add the parts together, or use our square footage calculator.
2. Find the area one tile covers. Multiply the tile width by the tile length. To allow for grout lines, add the gap to each side first.
3. Divide the room area by the tile area, using the same units for both.
4. Add extra for waste and round up to a whole tile.

Tiles = area to cover ÷ area of one tile, plus waste, rounded up

ExampleA 10 ft by 10 ft floor is 100 sq ft. A 12 in by 12 in tile covers 1 sq ft, so you need 100 tiles before waste. Adding 10% for cuts and breakage gives 110 tiles. With a 1/8 in grout gap the tiles sit slightly further apart, so the count drops to 108.

Tiles needed per 100 square feet

Figures assume no grout gap. The last column adds 10% for waste.

Tile size (in)	Area per tile	Tiles per 100 sq ft	With 10% waste
3 × 6	0.125 sq ft	800	880
4 × 4	0.111 sq ft	900	990
6 × 6	0.25 sq ft	400	440
12 × 12	1 sq ft	100	110
12 × 24	2 sq ft	50	55
18 × 18	2.25 sq ft	45	49
24 × 24	4 sq ft	25	28

How much extra tile to order

Tiles at the edges have to be cut, and some break or arrive damaged. These allowances are common rules of thumb. Ask your supplier or installer what they recommend for your layout.

Layout	Common allowance
Straight (grid) layout	about 10%
Diagonal layout	about 15%
Herringbone and other patterns	15% or more

It is also worth keeping a few spare tiles from the same batch for future repairs, because colors can vary between batches.

Working out boxes

Tile is sold by the box. Divide the number of tiles you need by the number in a box and round up. Enter the tiles per box in the calculator and it does this for you.

ExampleYou need 108 tiles and each box holds 10. 108 ÷ 10 = 10.8, so you buy 11 boxes.

Do grout gaps matter?

Each tile takes up its own size plus the gap around it, so wider grout lines mean slightly fewer tiles. For large tiles the difference is small. Follow the tile maker’s guidance for the joint width, and set the gap to 0 in the calculator if you prefer to ignore it.

Tips for measuring a tile job

• Measure the room at its longest and widest points, including into doorways and closets that will be tiled.
• For walls and backsplashes, enter the width and height of the wall as the length and width.
• Subtract large areas that will not be tiled, such as a tub, a vanity or a kitchen island.
• Check the box label for the number of pieces and the square feet per box.

Results are estimates based on the numbers you enter. Confirm quantities with your supplier, installer or contractor before ordering.

Frequently asked questions

How many 12×12 tiles do I need for 100 square feet?

Each 12 in by 12 in tile covers 1 square foot, so 100 tiles cover 100 sq ft. With 10% extra for waste, order 110.

How much extra tile should I buy?

Many installers allow about 10% for a straight layout and around 15% for diagonal or herringbone patterns, with more for rooms that have many corners. Ask your supplier or installer what suits your layout.

Does the grout gap change the number of tiles?

A little. Wider grout lines mean each tile takes up slightly more floor, so you need slightly fewer tiles. Set the gap to 0 if you would like to ignore it.

How do I work out how many boxes to buy?

Divide the number of tiles you need by the number of tiles in a box and round up. Enter the tiles per box and the calculator does this for you.

How many tiles come in a box?

It depends on the tile size and the manufacturer. The box label lists the number of pieces and the square feet it covers.

Can I use this for wall tile or a backsplash?

Yes. Enter the width and height of the wall as the length and width. For walls with windows or other openings, work out the net area first and enter it as the total area.