How to Use the Paver Calculator
Measure the area you are paving, length by width. Patios are rarely perfect rectangles: an L-shape is two rectangles added together, and a curved edge is close enough if you average the width — the waste factor swallows the difference. What matters is that you measure the paved surface itself, including the bit that disappears under edge restraints, not the fence-line dimension you started from.
Paver counts come from the module, exactly like bricks: one paver plus one joint in each direction. A 200 × 100 mm block laid with a 3 mm joint actually occupies 203 × 103 mm, so a square metre holds about 48 of them — the familiar "fifty per square metre tight-butted, forty-eight with joints" shorthand. Quick reference for the common sizes: 200 × 100 mm ≈ 48 per m² at a 3 mm joint (50 with none), and 200 × 200 mm ≈ 25 per m² tight-butted, 24–25 with joints. Bigger slabs mean fewer units per metre but more cutting where the pattern meets the edge.
The joint gap field matters more than people expect. Many blocks are moulded with spacer nibs that hold a joint automatically; smooth-edged slabs get whatever gap your laying leaves. A few millimetres per paver across a 6 m run is a whole extra paver's width — which is why a count calculated tight-butted comes up short on real patios. If your pavers have nibs, measure the gap they actually create (usually 2–3 mm) rather than guessing.
Waste covers cuts, breakages and the half-pavers that finish rows against edges. Ten percent suits a straightforward rectangle in running bond; use 12–15% for herringbone, 45° layouts, curved borders or anything with a circle in the middle, where every edge paver is cut at an angle. Keep the offcuts from the first cuts — later rows often reuse them.
Bedding sand is calculated from the area and your compacted depth — typically 25–40 mm of sharp (coarse) sand, screeded flat for the pavers to bed and settle into. The calculator adds a 20% allowance on top, because loose sand delivered by the bag or tonne takes up about a fifth more space than the compacted layer it becomes. So the sand row is the loose volume to order, not the depth you will see on the ground. One cubic metre of loose sharp sand at 3 cm compacted covers roughly 28 m².
Two things this tool deliberately does not count. Jointing sand — the fine kiln-dried sand swept into the gaps afterwards — is a separate bagged product with the coverage printed on the pack; narrow 2–3 mm joints use surprisingly little. And the sub-base is its own layer of compacted aggregate underneath everything: typically around 50–100 mm for patios and more for driveways, varying with ground conditions and use. Size it with the gravel calculator and plan it with the gravel sub-base guide. For layout decisions — patterns, borders, where to start — the paver quantity guide is the companion read.