Slab sizes such as 800x1600, 1200x1800 and 1200x2400 give the width and length of the slab in millimetres. An 800x1600 slab is 80 cm wide and 160 cm long; a 1200x2400 slab is 1.2 m by 2.4 m.
The figure is a nominal size. The actual or "work" size of a rectified slab is very close to it, usually within a fraction of a millimetre. Always ask for the work size and its tolerance in writing.
The three sizes compared
- 800x1600 mm is about 31.5 x 63 inches and covers 1.28 m² per slab. It is the easiest slab to handle, cut and ship.
- 1200x1800 mm is about 47 x 71 inches and covers 2.16 m² per slab. It suits bathroom walls, shower panels and vanity tops.
- 1200x2400 mm is about 47 x 94.5 inches and covers 2.88 m² per slab. It can run from floor to ceiling in many rooms and suits large floors.
Watch the units
Some catalogues list sizes in centimetres, such as 80x160 or 120x240. Others mix units by mistake, so a listing may say "800 cm" when it means 800 mm. If a size looks odd, ask the factory to confirm it in millimetres. For the full range of sizes, see porcelain slab sizes.
Nominal size and work size
Most slabs are rectified. After firing, the edges are ground square to a precise size, so slabs can be laid with narrow joints. A rectified 1200x2400 slab should measure very close to 1200 by 2400 mm.
Even so, two production runs can differ slightly. Factories sort output by size into calibres and mark them on the crate. Keep one calibre per design in each order, or the joints will not line up on site. The same logic for tiles is explained in 600x600, 600x1200 and 800x800 tile sizes.
What each size means for your buyers
Size affects more than the look. These are the practical points to pass on to your customers:
- Larger slabs need a flatter substrate, because any dip shows as uneven edges between slabs.
- Larger slabs need more people and lifting equipment, and some sites cannot get a 2.4 m slab up the stairs or into a lift.
- Fewer joints mean less grout to clean, which is a main selling point for floors and showers.
- Waste depends on the room. A 1200x2400 slab can leave large offcuts in small rooms, while 800x1600 may cut more efficiently.
What size means for your order
Square metres per slab change how you count stock. A price list per square metre and a stock list per slab must be converted with care. Ask the factory for slabs per crate, square metres per crate and gross weight per crate for each size.
Size also changes packing and container loading. Large slabs travel on edge in A-frames or crates, so the number per container depends on the frames as well as the weight. Ask for the factory's loading plan before you confirm the order.
Thickness is the other half of the description. A 1200x2400 slab at 6 mm and the same size at 12 mm are very different products, with different uses and weights.
Next step
We confirm sizes, calibres and packing in writing before production, and check them again at loading. To match slab sizes to your market and your fitters, book a free sourcing review.