Trade & construction Australia
Paver Calculator
Enter the area and the paver size. The calculator returns the number of pavers including a cut allowance, and the bedding sand and road base you will need under them — which is the part most paving estimates leave out.
Free, no signup Runs in your browser
0 for butt-jointed pavers
10% square, 15–20% with curves or a diagonal lay
100 mm foot traffic, more for vehicles
Pavers to order
—Before cuts
—
Pavers per m²
—
Bedding sand
—
Road base
—
How many pavers do I need?
Divide the area to be paved by the area of one paver, then add a wastage allowance for cuts. A 30 m² patio with 400 × 400 mm pavers needs 30 ÷ 0.16 = 188 pavers, plus about 10% for cuts — call it 207. Add more if the area has curves or angled edges.
How much to allow for cuts
The wastage figure depends almost entirely on the shape of the area and the pattern you lay.
A rectangular area laid in a running bond or stack bond generates cuts on two edges only. Ten per cent covers it comfortably.
A diagonal lay generates a cut at every edge paver, and each cut wastes most of the offcut because the angles do not pair up. Fifteen to twenty per cent is realistic.
Curves, circles and anything with a garden bed intruding into it are worse again. Twenty per cent is a floor rather than a ceiling, and it is worth counting the perimeter pavers on a sketch rather than guessing.
Order the extra with the original delivery rather than topping up later. Pavers are made in batches and colour varies between them, which is visible in a finished area even when the difference is slight on a single paver.
The layers underneath
Paving fails from below. The paver itself is rarely the problem; the base under it usually is.
Road base is the structural layer and it needs compacting in layers rather than dumped in one lift. A hundred millimetres compacted is the usual minimum for foot traffic. A driveway carrying vehicles needs substantially more, and that is a design decision rather than a rule of thumb.
Bedding sand sits between the base and the pavers and is there for levelling, not strength. Twenty-five to thirty millimetres screeded is standard. Thicker bedding sand feels like it gives more adjustment and produces a surface that ruts and settles unevenly.
Fall is the other thing to set before laying anything. Paving that drains toward a building rather than away from it is a problem no amount of good bedding will fix later.
How this is calculated
The paver count comes from one division. The materials underneath are the same volume arithmetic as any other layer.
effective paver area = (length + joint) × (width + joint) ÷ 1,000,000pavers = area ÷ effective paver areawith cuts = pavers × (1 + wastage %), rounded upbedding sand (m³) = area × depth ÷ 1,000road base (m³) = area × depth ÷ 1,0001 m³ of sand or road base ≈ 1.5 to 1.6 tonnes
The joint gap matters more than it looks. Three millimetres on a 400 millimetre paver is under one per cent per paver, but across a 30 square metre area it removes several pavers from the count — and getting it wrong in the other direction leaves you short.
The tonnage conversion for sand and road base is approximate because it depends on moisture and how compacted the material is when weighed. Suppliers sell by the tonne or by the cubic metre and the two do not convert exactly, so order by whichever unit the yard quotes in.
A worked example: a rear patio
A 30 square metre patio in 400 × 400 mm pavers with a 3 mm joint, 10% cut allowance, 30 mm of bedding sand and 100 mm of road base.
- Effective paver size with joint403 × 403 mm
- Area per paver0.1624 m²
- Pavers before cuts — 30 ÷ 0.1624185
- Add 10% for cuts204 pavers
- Bedding sand — 30 × 0.030.9 m³
- Road base — 30 × 0.13.0 m³
204 pavers, about 0.9 m³ of bedding sand and 3 m³ of road base.
That road base figure is the one that surprises people: at roughly 1.5 tonnes per cubic metre it is about four and a half tonnes of material, which is a truck delivery rather than a trailer.
What this calculator does not do
- Assumes a single paver size laid in a regular pattern
- Cut allowance is an estimate — count perimeter pavers on a sketch for an irregular area
- Sand and road base tonnage varies with moisture and compaction
- Base depths for vehicle loads should come from a design, not a default
Common questions
How many pavers per square metre?
Divide one square metre by the paver area including the joint. A 400 × 400 mm paver with a 3 mm joint covers 0.1624 m², so about 6.2 pavers per square metre.
How much wastage should I allow for pavers?
Ten per cent for a square area in a straight lay, 15 to 20 per cent for a diagonal lay or an area with curves. Order the extra with the first delivery so the batch colour matches.
How thick should bedding sand be?
Twenty-five to thirty millimetres screeded. Thicker sand seems more forgiving during laying and settles unevenly afterwards, which shows up as dips within the first year.
How much road base do I need under pavers?
A hundred millimetres compacted is typical for foot traffic. Vehicle loads need considerably more, and the depth should come from the design rather than a general figure.
Do I need to compact the road base?
Yes, in layers of about 50 millimetres with a plate compactor, watering lightly as you go. Uncompacted base settles under load and takes the paving down with it.
Where these numbers come from
- Standard area geometry — coverage per unit Fixed formula; base depths are general industry practice, not a code requirement
Method last reviewed 2026-10-28 This calculator uses fixed rules rather than rates that change, and its method is re-checked against the sources above at least once a year. Out of date? Tell us and we will fix it.
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