It is normal practice to order at least 10% for wastage and cuts. This may increase if you have a complicated laying pattern such as Octagons laid on the diagonal aka diamonds and dots. This increases the requirement to between 13 and 15%. Many professional installation comopanies add 20% as standard which allows cover for breakages and selection.
Measure length by breadth in metres. Then multiply L x B to get the area.
With a complicated space with turns and dog legs, break down the area into separate rectangles and add together.
Please note that unfortunately you can expect a few breakages which occur during transit, as natural stone tiles are not boxed and can experience some rough handling while being swapped from vehicle to vehicle.
When tiling try and start from a centre point working towards the walls.
Where there is a Cut Tile such as at the beginning or end of a row, always try to use a broken tile or one with the corner missing.
