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Tiles Shade and Caliber. What are they?

Porcelain stoneware is a natural product, made up of natural components: kaolin clay, kaolins, sand, feldspars, and synthetic pigments. The behavior of these materials after a strong pressing process and firing at temperatures of over 1250 degrees Celsius is hard to predict. In this article, we are going to tell you about two very important parameters: tiles shade and caliber.

During the manufacturing process, each tile reaches its own actual dimension and tone of color. For this reason, at the end of the productive cycle, porcelain stoneware is selected according to shade and caliber.

When purchasing tiles, it is important to make sure they all have the same shade and caliber.


Shade is the tone of color of different tiles that are part of the same batch. It is an aesthetic parameter that must be taken into consideration when purchasing tiles. At the end of the technological manufacturing process, a porcelain stoneware batch is selected and assigned a specific “shade”. It will be indicated on the package and on its documents. Usually, it is a combination of letters and digits, like “AB4” or “BC6”.



The second important parameter, which strongly affects the quality of tile laying, is caliber. A tile’s caliber indicates its effective size. Very often we are asked this question: I bought porcelain tiles, size 60×60, I opened the box, measured it, and it really was 59.6x59x6. Why isn’t there a correspondence?”

Let’s break this down: 60×60 cm is the nominal dimension of the tile, while 59.6×59.6cm is the actual size of a tile caliber “6”. Why is that?

During manufacturing, each tile reaches its own dimension, but when it comes to slightly different tiles you will never achieve a minimum joint size, or even manage to combine surfaces and sizes. Basically, you will never have a satisfying aesthetic result.


So, what should you do?

For small formats such as 30×30 or 45×45, tiles batches are sent to the choosing line, where tiles are measured and grouped according to equal actual sizes, or calibers.

In the case of large size tiles (30х60, 60х60, 60х120, 80х80, 80х160, etc.) all products are sent to the edges rectification line. After rectification, all tiles will have the same actual size and perfectly perpendicular corners.


These are the tiles you will find in the box. The actual measure, meaning the caliber, will be mentioned on the package.


The nominal size is what tiles are named after (i.e. porcelain tiles, 60x60cm), which is also found on the tile’s package. The actual size is the result of the manufacturing process (it might be, for example, 59.6×59.6cm) and that’s the caliber, which can also be found on the package.


Actual sizes tend to be slightly smaller than the nominal ones, so we advise reading the package carefully to know the real dimensions of your product.

Italon’s standard caliber for rectified porcelain tiles is 6.

On the packages and on our official website, in the documents section, you will find a chart with all the calibers for Italon’s products. You should keep this in mind when buying tiles and when laying them down.

If you are working on a renovating project and you wish to know what to look for, first and foremost, when choosing tiles for your bathroom, kitchen, living room, hallway and house in general, we recommend reading the “Porcelain tiles: everything you need to know” article, in which we tell you about the main characteristics of tiles.