Understanding your result
The headline is the number of pavers to buy, including the waste allowance for your pattern. Pavers are usually sold by the pallet or by the layer, so ask your supplier how many are in each and round up to their unit.
The gravel base and bedding sand are each given as a volume and as a weight. Landscape yards sell these by the ton, so the weight is what you will order. Both include an allowance: 15% on the base, because it shrinks when compacted, and 10% on the sand, because some is lost into the surface of the base and some is left over after screeding.
Depth to dig out is the total depth below your finished patio level. It adds the base, the sand and a standard paver thickness of 2⅜ inches (60 mm). Dig to this depth, plus any slope you need for drainage, before the first load of gravel goes in.
The drawing shows the three layers in section, with your depths marked.
How we calculate this
The area of one paver is its width times its length. In inches, divide by 144 to get square feet.
The base area is larger than the patio because the base extends 6 inches past the paving on each side. For a circular patio the diameter is increased by 1 foot instead.
For weights, the calculator uses 2,800 pounds per cubic yard for compacted base material and 2,700 for bedding sand. The gravel calculator lets you change these if your supplier’s figures differ.
The assumptions behind the numbers
| Assumption | Value used | Why |
|---|---|---|
| Waste, straight patterns | 5% | Cuts only at the edges |
| Waste, herringbone or 45° | 10% | Every edge paver is cut, and offcuts are small |
| Waste, curves and circles | 15% | Many cuts, few reusable offcuts |
| Joints | Ignored | Slightly overestimates the count, which is the safe side |
| Base overhang | 6 in (15 cm) each side | Supports the edge restraint |
| Base compaction | 15% extra | Typical loss when crusher run is plate-compacted |
| Sand allowance | 10% extra | Loss into the base surface and screeding surplus |
| Paver thickness | 2⅜ in (60 mm) | The common thickness for patios and paths. Used only for the digging depth |
| Edging spikes | One per foot (30 cm) | A common spacing. Follow the edging maker’s instructions |
Assumptions last reviewed October 3, 2026.
Jointing sand is not calculated. Coverage varies enormously with joint width and paver thickness, and every product prints its own coverage table on the bag. It is listed on the shopping list as a reminder.
Two worked examples
A herringbone patio on clay soil
A patio 16 feet by 12 feet is being laid in herringbone with 6 × 9 inch pavers. The soil is heavy clay, so the base is increased to 6 inches.
- Area: 16 × 12 = 192 sq ft
- One paver: 6 × 9 ÷ 144 = 0.375 sq ft
- Pavers: 192 × 1.10 ÷ 0.375 = 563.2, so 564 pavers
- Base area: 17 × 13 = 221 sq ft
- Base volume: 221 × 0.5 × 1.15 = 127 cu ft, which is 4.7 cu yd, or 6.6 tons
- Sand: 192 × 1 ÷ 12 × 1.10 = 17.6 cu ft, or 0.88 tons
- Edge restraint: 2 × (16 + 12) = 56 ft
- Depth to dig: 6 + 1 + 2⅜ = 9⅜ in
Notice how much of this job is gravel. Six and a half tons of base against less than a ton of sand. On most patios the base is the heaviest and the most laborious part, and it is the part nobody sees.
A garden path, in metric
A straight path 8 meters long and 1.2 meters wide is being laid with 200 × 200 mm pavers in a simple stack pattern, on 10 cm of base and 2.5 cm of sand.
- Area: 8 × 1.2 = 9.6 m²
- One paver: 0.2 × 0.2 = 0.04 m²
- Pavers: 9.6 × 1.05 ÷ 0.04 = 252 pavers
- Base: about 1.44 m³ after compaction allowance, or 2.4 tonnes
- Sand: about 0.26 m³, or 0.42 tonnes
- Edge restraint: 2 × (8 + 1.2) = 18.4 m
A path this narrow is only six pavers wide, so there are no cuts across the width at all if the path is set out to suit the paver. That is worth doing. Setting the width to a whole number of pavers saves cutting, saves waste, and looks better.
Common mistakes
- Counting only the pavers. The base and sand are most of the material and most of the work. Price them before you commit to a size.
- Skimping on the base. A thin base is the most common reason patios sink and heave. It cannot be fixed afterward without lifting everything.
- Using too much sand. One inch, no more. Sand is for bedding, not for leveling out a poorly graded base.
- Using the wrong waste figure. Herringbone at 5% runs short. Diagonal patterns need the full 10%.
- Forgetting the edge restraint. Without it the outside pavers creep outward and the joints open up across the whole patio.
- Ordering from two batches. Paver color varies between production runs. Order everything at once, with the waste included, and mix pavers from several pallets as you lay.
- Laying dead level. A patio needs a slight fall away from the house, about an eighth to a quarter of an inch per foot, so that water runs off.
Printable shopping list
Print shopping list gives you the full order on one page: pavers, base gravel, bedding sand, edge restraint and spikes, with a reminder for jointing sand. Suppliers will want the gravel and sand in tons and the pavers in square feet or pallets, so take the breakdown table with you as well. If you are renting a plate compactor, book it for the day the base arrives.
Questions people ask
- How many pavers do I need per square foot?
- It depends on the paver. Standard 4 × 8 inch brick pavers take 4.5 per square foot. 6 × 6 inch pavers take 4, 6 × 9 inch take 2.67, 12 × 12 inch take 1, and 16 × 16 inch take about 0.56. Divide 144 by the paver's width times its length in inches.
- How much waste should I allow for pavers?
- About 5% for straight patterns such as running bond, where only the edges are cut. Allow 10% for herringbone or any pattern laid at 45 degrees, because every edge paver is cut. Allow 15% for curved edges and circular patios.
- How deep should the gravel base be under a patio?
- Four inches of compacted base is the usual minimum for a patio or path on well-drained soil. On clay, or where the ground freezes hard, 6 inches or more is safer. Driveways need 8 to 12 inches.
- How much sand goes under pavers?
- One inch, screeded level over the compacted base. More is not better. A thick sand bed shifts and settles unevenly, and the pavers go with it.
- Why does the base need to be bigger than the patio?
- The edge restraint has to sit on compacted base, not on soft soil, or the outside row of pavers will tip outward. Extending the base about 6 inches past the paving on every side gives the edging something solid to be spiked into.
- Does the calculator include the joints between pavers?
- No. It divides the area by the size of the paver itself, without joints. Joints are narrow, usually an eighth of an inch, so ignoring them overestimates the count very slightly, which is the safe direction.
Built and reviewed by Bertha
Last updated · How we work out our numbers