How to plan a paver patio
- Mark the patio outline and measure it. Use "Other" for irregular shapes and enter the area and perimeter.
- Enter the length of any edge that sits against the house or a wall, since it needs no edge restraint.
- Enter the paver size and thickness from the product sheet. The default thickness is 2 3/8 inches (60 mm).
- Set the base depth for your soil and use, and the sand bedding depth.
How the materials are calculated
Pavers = area × 144 ÷ (paver length × width) × (1 + extra), rounded up
Base (cu yd) = area × base depth ÷ 12 ÷ 27 × (1 + compaction allowance)
Base (tons) = base cubic yards × tons per cubic yard
Sand (cu ft) = area × sand depth ÷ 12
Dig depth = paver thickness + sand depth + base depth
Worked example
A 12 by 16 foot patio is 192 square feet. With 4 by 8 inch pavers that is 192 × 144 ÷ 32 = 864 pavers, or 908 with 5% extra. A 6 inch base with a 15% compaction allowance is 4.09 cubic yards, about 6.1 tons at 1.5 tons per yard. The 1 inch sand layer takes 16 cubic feet, or 32 half-cubic-foot bags. You dig down 9 3/8" and remove about 5.6 cubic yards of soil.
Pavers per square foot
| Paver size | Pavers per sq ft |
|---|---|
| 4 × 8 in | 4.5 |
| 6 × 9 in | 2.67 |
| 12 × 12 in | 1 |
| 16 × 16 in | 0.56 |
About the defaults
- Base depth, 6 inches: Unilock's recommendation for patios and walkways, and the top of ICPI's 4 to 6 inch range for walks.
- Compaction allowance, 15%: crushed base shrinks as it is compacted, but there is no single published figure. This default is an assumption; ask your supplier and change it.
- 1.5 tons per cubic yard: between the 1.35 tons often given for crushed stone and the 1.55 tons for crusher run. Your supplier's figure for their base material is better.
- 5% extra pavers: the minimum overage in Unilock's specification. Raise it for patterns with many cuts.
Frequently asked questions
How many pavers do I need per square foot?
Divide 144 by the paver's length times width in inches. A 4 by 8 inch paver works out to 4.5 per square foot, a 6 by 9 to 2.67, and a 12 by 12 to exactly 1. The table on this page lists more sizes.
How deep should the gravel base be for a patio?
The Interlocking Concrete Pavement Institute (ICPI) gives a minimum base of 4 to 6 inches for walks and 6 to 8 inches for driveways. Belgard lists 4 inches as the minimum for patios, and Unilock recommends 6 inches for patios and walkways. Soft or poorly drained soil may need more, so ask your supplier or a local installer.
How much sand goes under pavers?
ICPI shows a nominal 1 inch bedding layer of coarse sand, screeded to 1 to 1 1/2 inches before the pavers are compacted into it. Do not use the sand layer to fix low spots; level the base instead.
How many extra pavers should I order?
Unilock's specification calls for at least 5% extra. Patterns with many cuts, such as herringbone or a curved edge, need more. Spare pavers from the same batch are also handy for future repairs.
How many tons of gravel do I need for a 12 by 16 patio?
A 12 by 16 foot patio is 192 square feet. A 6 inch base is 96 cubic feet; with a 15% allowance for compaction that is 4.09 cubic yards, or about 6.1 tons at 1.5 tons per cubic yard.
How deep do I need to dig for a paver patio?
Dig to the paver thickness plus the sand plus the base below the finished surface. With 2 3/8 inch pavers, 1 inch of sand and a 6 inch base, that is 9 3/8 inches. Add the slope you need for drainage on top of that.