understanding tile size variation
how Australian Standards define tile size
The Australian Standard exists to make sure tile products meet clear quality and consistency guidelines, and to help customers understand what level of variation is considered normal. Under the Standard, tiles are allowed a small tolerance in length and width of ±0.6% from the manufacturer’s intended size, up to a maximum of ±2mm. For example, a 600 × 600mm tile may naturally measure anywhere between 598mm and 602mm. This level of variation is completely acceptable and is not considered a defect.
What does “nominated work size” mean?
To help explain tile sizing clearly, tiles are described using three size terms:
Nominal Size
This is the approximate size used to describe and label the product, such as 300 × 300mm or 600 × 600mm. This is the size you’ll see on the box and is used for general identification.
Work Size
This is the size the manufacturer is aiming to produce and is the true working dimension of the tile. It may differ slightly from the nominal size and can vary between batches (also known as calibre). Because of this, tiles with the same nominal size can still have slightly different work sizes.
Important to know: When tiles with different work sizes are used together, a wider grout joint may be required to comfortably accommodate these variations and ensure a quality finish.
Actual Size
This is the physical size of the tile once manufactured, measured in accordance with the Australian Standard.
How
do I know if my tiles comply with the Standard?
Compliance is determined by measuring ten tiles across both their length and width (a total of 40 measurements) to calculate the average actual work size. The Australian Standard tolerances are then applied to this average.
For example, if the average work size is 297 × 599mm, individual tiles may reasonably fall between 295–299mm and 597–601mm. Tiles within this range are considered compliant, acceptable, and of First Quality.
