How to calculate the number of tiles for your flooring and coverings

It’s time to buy the tiles for your living room or bedroom flooring and your bathroom or kitchen coverings. But how many tiles should you order?

And what waste factor should you consider? These are very important questions because, if you realise that you don’t have enough tiles only when you’re laying them, it could be a big problem. Even if you find the same tiles, the colour might be slightly different, and you’ll end up with mismatching floors.

How many tiles should you order?

To calculate the number of tiles you need, measure the space to be tiled and add the waste factor, i.e. the percentage of tiles wasted while drilling or cutting them. The waste factor must consider the size of the joints because larger joints mean fewer tiles and the laying pattern. For example, a horizontal pattern requires fewer tiles than a diagonal one.

The size of the tile also affects the waste factor. Smaller tiles (e.g. 20x20 cm or 30x30 cm) entail a lower waste factor than larger ones. Then, you have to consider any critical element you may have to work around while laying the tiles. For example, columns or irregular shaped rooms (trapezium or triangle) imply a higher waste factor. As a rule of thumb, the larger the room to be tiled and the lower the waste factor.

Let’s say you need to tile the flooring of a 200 sq.m home with standard rectangular rooms without any columns or other critical elements. You’ve opted for medium-sized porcelain stoneware tiles (e.g. 60x60 cm) in a straight pattern. The waste factor to consider is 10%, so you’ll need to order 220 sq.m of tiles. Now, let’s say you want to tile the walls of a small bathroom (8 sq.m) with 60x60 cm tiles. In this case, the waste factor to consider is 20%, so you’ll need to order a number of tiles equal to 9.6 sq.m.

In general, to calculate how many tiles should you order for your flooring, you need to measure the exact surface area and add a 10% waste factor. So, for the flooring of a room measuring 4.00x5.00 m, we’ll have an overall surface area of 20 sq.m, to which we must add 10%. Therefore, we need to order a number of porcelain stoneware floor tiles equal to 22 sq.m.

To know how many porcelain stoneware tiles we need for our bathroom walls, we need to calculate the perimeter of the room and multiply it by the height of the wall area you want to tile. To keep things simple, we recommend not to subtract the dimensions of the door and window openings but to add an 8% waste factor.

For the kitchen’s wall coverings, you only have to consider the wall or walls you want to cover with porcelain stoneware tiles and multiply the length by the height of the wall area to tile. If you want to install a backsplash between the base of the cabinetry and the wall units, you’ll have to consider these furnishings and start 80 cm from the ground up to 160 cm in height. Therefore, you have to multiply the length of the wall you want to tile by 80 cm. In both cases, it’s good practice to consider an 8% waste factor.

However, we recommend keeping a few extra tiles for future repairs. Finally, we suggest not to change the laying pattern once you’ve ordered the tiles. If, for example, you chose a horizontal pattern but then opt for a diagonal one, you’ll end up running out of tiles while you’re laying them.