Paver Calculator
Work out how many pavers or slabs a patio or path needs, with a cutting allowance and cost.
How to use this calculator
- 1Measure the area. For an irregular space, split it into rectangles, work each out, and add them.
- 2Set the unit you measured in — the calculator converts everything for you.
- 3Check the coverage figure against the bag or tin you are actually buying; it varies between brands.
- 4Leave the waste allowance on. Running short mid-job costs far more than one spare unit.
How the calculation works
Units = ⌈ (Area × (1 + waste)) / Area of one piece ⌉- Area
- Surface area of the job
- waste
- Allowance for cuts, breakage and spillage
- ⌈ ⌉
- Round up — you cannot buy a fraction of a unit
Every dimension is converted to metres internally, so feet, yards and metres can be mixed with inches or centimetres without error.
Enter the paver dimensions excluding any joint gap. On a sand-set patio the joints are a few millimetres and the difference is small; on a mortared job with 10 mm joints across a large area it is worth adding the joint width to each dimension.
The laying pattern drives the cutting allowance more than the area does. A straight stretcher bond wastes least; 45-degree diagonal and herringbone patterns cut every perimeter paver and need 15% or more.
Worked example
A 20 × 12 ft area
- 1.20 ft × 12 ft = 240 sq ft, which is 22.30 m².
- 2.Divided by the coverage per paver, that gives the raw requirement.
- 3.A 10% waste allowance is added, then the figure is rounded up to whole pavers.
Result: See the result panel — it updates live as you change the numbers.
What this assumes, and where it stops
Assumptions
- The area is flat and regular as described. Slopes, steps and obstructions change the quantity.
- Coverage figures are the manufacturer’s stated values, which assume good conditions and an even surface.
- The area is regular and laid in a straight pattern unless the waste allowance is raised.
Limitations
- This estimates material only — not labour, tools, delivery, hire or disposal.
- Manufacturer coverage varies between brands and batches. Always check the packaging.
- Does not include the sub-base, bedding sand, edging restraint or jointing sand, all of which are separate materials.
- Curved or irregular edges generate far more cutting waste than a percentage allowance captures — measure those separately.
Common questions
How many pavers are in a square metre?
It depends entirely on paver size. A common 200 × 100 mm block is 0.02 m², so 50 per square metre. A 450 × 450 mm slab is 0.2025 m², so about 5 per square metre. Enter your actual paver dimensions rather than relying on a rule of thumb.
How much extra should I order for cutting?
About 5% for a straight-laid rectangular area, 10% for most jobs, and 15% or more for diagonal or herringbone patterns where every edge paver is cut. Curved edges need more still. Ordering short is expensive, because a later batch may not colour-match.
Formula and content last reviewed on .
Results are estimates for information only, not professional advice.
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