Paver Calculator

Paver Calculator: How Many Pavers Do I Need?

Pavers are bought one by one, but the ground underneath them is bought by the cubic yard, and a patio that runs short of either one stops the job cold. If you are asking how many pavers do i need, the honest answer has three parts: the pavers themselves, the compacted gravel base below them, and the thin layer of bedding sand in between. This page works out all three for you, in imperial or metric units, shows every formula it uses, and adds a waste allowance so the number you order is the number that finishes the job.

Quick answer

With standard 4 × 8 in brick pavers, a 100 sq ft patio needs 450 pavers, before any waste allowance. A 4 × 8 in paver covers 32 square inches, and at 4.5 pavers per sq ft the counts below follow directly. They are net figures with nothing added, so most people then allow about 10% extra for cuts and breakages — the calculator further down adds that allowance for you.

Project	Area	Pavers needed (4 × 8 in)
Patio	100 sq ft	450 pavers
10 × 10 ft patio	100 sq ft	450 pavers
12 × 12 ft patio	144 sq ft	648 pavers
Patio	200 sq ft	900 pavers
15 × 20 ft patio	300 sq ft	1,350 pavers

Check any row by hand: divide the area by the area of one paver. A 12 × 12 ft patio is 144 sq ft, one 4 × 8 in paver covers 0.222 sq ft, and 144 ÷ 0.222 is 648 pavers. The full working is in the worked example below.

How the calculation works

Every paver project is a sandwich of three layers. On top sit the pavers themselves, the part you see and walk on. Under them is a 1 in layer of coarse bedding sand, which gives each paver a flat, even bed to sit in. Under that is the compacted gravel base, the layer that actually carries the weight and stops the surface from sinking and shifting. The calculator treats each layer separately, but all three start from the same measurement: the area of your project.

• Project area: length × width for a rectangle, or π × (diameter ÷ 2)² for a circle.
• Pavers: project area ÷ the area of one paver, then multiplied by (1 + waste allowance) and rounded up, because you cannot lay part of a paver across a whole space. One paver area is its length × its width, in the same units as the project.
• Base gravel: project area × base depth gives the volume. In imperial units that volume in cubic feet is divided by 27 to get cubic yards, and cubic yards × 1.4 gives tons, using a typical gravel density of 1.4 tons per cubic yard.
• Bedding sand: project area × 1 in, the standard bedding depth, converted the same way into cubic yards or cubic metres.

The base and the sand are calculated on the same area as the pavers for a simple reason: both layers run under the whole surface, edge to edge. The base does not stop short of the border and neither does the sand, so each layer covers exactly the footprint the pavers cover — only its depth is different. That is why one area measurement, three depths, and a paver size are all this calculator needs.

Worked example

Take a 12 × 12 ft patio laid with standard 4 × 8 in pavers, a 4 in gravel base, and the default 10% waste allowance. Here is every step, using the same formulas as the calculator above.

• Step 1 — area: 12 ft × 12 ft = 144 sq ft.
• Step 2 — pavers, net: one 4 × 8 in paver covers 4.5 per sq ft, so 144 × 4.5 = 648 pavers.
• Step 3 — pavers with waste: 648 × 1.10 = 712.8, which rounds up to 713 pavers to buy.
• Step 4 — base gravel: 144 sq ft × 4 in deep = 48 cu ft, and 48 ÷ 27 = 1.78 yd³. At 1.4 tons per cubic yard that is about 2.5 tons.
• Step 5 — bedding sand: 144 sq ft × 1 in deep = 12 cu ft, and 12 ÷ 27 = 0.44 yd³.

Set the calculator to 12 × 12 ft, 4 × 8 in pavers, 0% waste and a 4 in base and it returns exactly 648 pavers, 1.78 yd³ of base and 0.44 yd³ of sand — then change the waste to 10% and the paver count becomes 713, matching the steps above.

How deep should the base be?

For patios and garden paths, 4 in of compacted gravel is the standard base: enough to spread foot traffic over the soil below and to ride out ordinary wet and dry weather without rocking. Driveways carry far heavier, concentrated loads, so they need 6–8 in. Soil matters as much as traffic. Firm, sandy, free-draining ground can work with the standard depth, while soft or clay soil holds water, moves more, and needs a deeper base — on poor ground, adding depth is cheaper than rebuilding a sunken surface.

Whatever depth you choose, compact the base in lifts — layers of about 2 in at a time — running a plate compactor over each lift before adding the next. A single deep layer only compacts at the top and stays loose underneath. Add the layers up before you dig: excavation depth is base depth, plus 1 in of sand, plus the thickness of the paver itself. For a typical patio that means digging about 7 in down, so the finished surface sits flush with, or a little above, the ground around it. One common mistake to avoid: the bedding sand is screeded loose at 1 in and is not compacted before the pavers are laid. It compacts later, once the pavers are down and the compactor passes over the finished surface.

Paver sizes

Bigger pavers cover ground faster and need fewer units, but they are heavier to handle and less forgiving on anything but a flat base. The table shows how many of each preset size it takes to cover one square foot, before waste.

Paver size	Pavers per sq ft	Common uses
4 × 8 in	4.5	The classic brick paver — patios, paths and driveways, and the standard for herringbone
6 × 6 in	4	Small patios, borders and edging courses
6 × 9 in	2.67	Patios and driveways, often mixed with 6 × 6 in
12 × 12 in	1	Simple patios and garden paths
12 × 24 in	0.5	Modern patios, terraces and stepping-stone runs
24 × 24 in	0.25	Large patios and terraces with a clean, open look

UK readers will usually know the larger sizes as paving slabs rather than pavers, and the metric presets in the calculator follow those slab sizes. The standard base material in the UK is MOT Type 1, a crushed aggregate that compacts hard — it does exactly the job of the gravel base described on this page, so the same depths and volumes apply.

Patterns, edging and joint sand

The pattern you lay affects both strength and waste. Running bond and stack bond are the simplest to lay and waste the least, because most cuts are straight and the offcuts are easy to reuse. Herringbone, with pavers at 45 or 90 degrees interlocking in both directions, is the strongest pattern for driveways, where turning wheels try to push pavers apart — but the angled edge cuts push waste up, which is why the allowance guide in the calculator allows it 10–15%.

Edge restraints are not optional. A paver surface is only locked together while its edges are held: without a restraint on every open side, pavers slowly creep outward, the joints open, and the surface loosens. Fit the restraint — a purpose-made edging, a concrete haunch, or a solid border course — before you judge the job finished. Finally, sweep polymeric sand into the joints and activate it as its label directs. It sets firm, locks the surface together and suppresses weeds far better than plain sand. How much you need depends on joint width and paver thickness, which vary too much for a fair calculator figure, so check the coverage printed on the bag against your area before you buy.

Frequently asked questions