Paving Slab Calculator
How many paving slabs do I need?
Pick your slab size and enter the patio's length and width, and the calculator divides the area by the slab area and adds 10% for cuts and breakages. The wastage margin matters more than people expect: any patio that is not a perfect rectangle needs slabs cut to fit the edges, and cut offcuts rarely fit anywhere else.
Measure the area to be paved, allow for the pointing gaps between slabs (they slightly reduce the number needed but it is safer to ignore them as extra margin), and order all your slabs in one batch so the colour matches, as stone and concrete shades vary between production runs.
Frequently asked questions
Is the paving slabs calculator free?
Yes. It is completely free, with no sign-up and nothing to install. It runs entirely in your browser.
How accurate is it?
It gives a reliable estimate for ordering based on standard UK figures, but real quantities vary with ground conditions, wastage and how materials settle. Always add a margin and confirm with your supplier before buying.