Calibre (ceramics)
In ceramics, the calibre (caliber in US English) is the variation of the real size of a piece from its nominal size, caused by shrinkage in the kiln. Pieces are classified by calibre with a code on the box, because two different calibres do not fit with the same joint on the same surface.
Why does the calibre of a tile vary?
A nominal 60 × 60 tile may come out at 59.6 or 60.2 centimetres depending on the firing. Rectification reduces the problem in porcelain tiles but does not remove it. Like the shade, the calibre is an attribute of the batch that the warehouse must respect when reserving and shipping, and the ERP must control.