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Free tool

How much paving do I need?

Enter your area and we'll work out the slabs and packs — with a 10% allowance for cuts and breakage built in, always rounded up to whole packs.

Coverage calculator

Totals shown inc. VAT with the ex-VAT figure alongside · includes a 10% allowance for cuts & waste.
Laying patterns

Which pattern are you laying?

The pattern changes how many cuts you make at the edges — and that changes how much extra to order. Pick a pattern to see honest wastage guidance for it.

Stack bond ~5–10% extra for cuts

Slabs line up in a straight grid, with every joint running unbroken in both directions. Crisp and contemporary — and unforgiving of sloppy setting-out, because every misalignment shows.

Cuts only fall at the perimeter, so allow around 5–10% extra for cuts and breakages.

Stretcher (running) bond ~5–10% extra for cuts

Each row is offset by half a slab, like brickwork. The most common and most forgiving layout — staggered joints disguise small size variations.

Allow around 5–10% extra; the offcut that ends one row often starts the next, so little is wasted.

Herringbone 45° ~15% extra for cuts

The classic zigzag laid diagonally at 45° to the patio edge. The strongest interlock and the most dramatic look — but every perimeter slab needs an angled cut.

Allow around 15% extra: the diagonal edge cuts are numerous and the triangular offcuts rarely reuse.

Herringbone 90° ~10% extra for cuts

The same zigzag turned square to the edges. You keep the interlocked look while the perimeter cuts stay straight and simple.

Allow around 10% extra — square edge cuts mean the offcuts reuse far more often than at 45°.

Basket weave ~10% extra for cuts

Pairs of slabs laid in alternating directions, like a woven basket. A traditional cottage-garden look that works best with 2:1 slabs.

Allow around 10% extra for the perimeter cuts and pattern matching.

Mixed-size 'Roman' pattern ~10% extra for cuts

A repeating layout of three or four slab sizes — the classic patio-pack look. Buy project packs in the maker's mixed ratio rather than picking sizes yourself.

Follow the pack ratios and allow around 10% extra; running one size short mid-pattern is the real risk.

Stepping stones Minimal (~5%) for cuts

Individual slabs spaced out through grass or gravel to form a path. No jointing and usually no cutting at all.

Minimal extra needed — around 5%, or simply a spare slab or two in case of damage.

Wastage figures are the allowances the trade typically works to — your exact figure depends on the shape of your area and how many edges need cutting. The cutting & laying patterns guide shows worked examples for every pattern.

How to use it

  1. Measure your area — length × width in metres (or enter your total m² directly).
  2. Check the allowance — a 10% cuts-and-breakage allowance is added automatically, so you're never caught short mid-job.
  3. Read off slabs and packs — the result is always rounded up to whole packs, using the real pack sizes shown on each product page.

How the rounding works

Paving is made and sold in fixed units, so the calculator never hands you a fraction you can't buy. Your measured area is bumped up by the 10% allowance, converted into slabs using the real slab coverage for the range, then rounded up — first to whole slabs, then into full packs plus any loose slabs. Rounding up is deliberate: running out of matching stone mid-patio costs far more than a spare slab or two, and batches can vary in shade between orders.

Planning the whole job? The guides library covers the rest — the ground-prep guide works out sub-base and bedding quantities, and the coverage quick-answer explains the maths behind this tool.

Ready to pick your slab? Browse Kandla Grey or all paving.

Coverage is an estimate to help you order confidently. On any product page you'll see the exact pack size and per-m² price for that range.