How to use the paver base calculator
- Enter the patio or walkway size. Add 6–12 inches on each side beyond the pavers: the base should extend past the edge restraint so the edge pavers are fully supported.
- Enter the finished, compacted depth of base you want.
- Choose the base material. Dense-graded aggregate (often sold as crusher run, road base, "paver base" or 3/4-inch minus) is standard because its fines fill the gaps and it compacts hard.
- Keep the 20% compaction allowance unless your supplier gives a different figure, and add 5–10% waste.
How deep should paver base be?
Guidance published for interlocking concrete pavers by ICPI (now part of the Concrete Masonry & Hardscapes Association) commonly calls for about:
- 4–6 inches of compacted base for patios and walkways
- 8–12 inches for residential driveways
- More in clay soils, wet sites or cold climates with deep frost
Base should be placed and compacted in lifts of a few inches at a time; one thick layer will not compact properly at the bottom.
The formula
Loose volume (cu ft) = area × compacted depth (in) ÷ 12 × (1 + compaction %) × (1 + waste %)
Tons = cubic feet × density (lb/ft³) ÷ 2,000
The default density of 110 lb/ft³ (about 1.49 tons per cubic yard, loose) is a typical figure for dense-graded base. It is a little heavier than the 105 lb/ft³ that The Engineering ToolBox lists for ordinary dry gravel because the stone dust fills voids. Compaction then squeezes that loose material into less space, which is why you need more than the plain area × depth.
Worked example
A 12 × 12 ft patio with a 4-inch compacted base, 20% compaction allowance and 5% waste:
- Area: 144 sq ft
- Compacted volume: 144 × 4 ÷ 12 = 48 cu ft
- Loose volume to order: 48 × 1.20 × 1.05 = 60.5 cu ft = 2.24 yd³
- Weight at 110 lb/ft³: 6,653 lb = 3.33 tons
- In 0.5 cu ft bags: 121 bags
Over 120 bags is a strong argument for bulk delivery. Many yards sell base by the ton at a fraction of the bagged price.
Paver patio layers in order
- Excavate: base depth + 1 inch of bedding + paver thickness, minus any height above grade.
- Compact the soil; add geotextile on clay or soft soils.
- Base in compacted lifts (this calculator).
- 1 inch of bedding sand, screeded flat — see the paver sand calculator. Some installers use stone dust instead.
- Pavers, edge restraint, joint sand, final compaction.
Tips
- Slope it now. Build the slope (about 1/4 inch per foot away from the house) into the base, not the sand.
- Dampen before compacting. Slightly moist base compacts far better than dry base.
- Budget option: recycled concrete base can cost less; compare in the crushed concrete calculator.
Frequently asked questions
How much paver base do I need for a 12 × 12 patio?
At 4 inches compacted, about 48 cu ft before allowances. Adding 20% for compaction and 5% waste gives about 2.2 cubic yards, or roughly 3.3 tons of dense-graded base.
How much does paver base compact?
Loose dense-graded aggregate typically compacts by about 15–25%. This calculator uses 20% by default; ask your supplier for their figure.
How many bags of paver base per square foot?
At 4 inches compacted with 20% compaction, each square foot needs about 0.4 cu ft of loose base, so roughly one 0.5 cu ft bag per 1.25 sq ft.
Can I use gravel instead of paver base?
Clean, angular crushed stone can work as a base, especially for permeable pavers, but rounded gravel such as pea gravel does not lock together and should not be used under pavers.
How thick should paver base be for a driveway?
Typically 8–12 inches of compacted base for a residential driveway, placed and compacted in lifts, and more on weak soils.