Patio base calculator
A paver patio is mostly what is under it. The base is ordered loose and compacts to about two-thirds of its delivered depth, which is why a base estimate that ignores compaction comes up short by a third.
Patio area
How this is calculated
- Base gravel, compacted = area × (base depth ÷ 12) in cubic feet.
- Order loose = compacted × 1.35, the usual factor for crushed stone compacted in lifts.
- Sand = area × (sand depth ÷ 12) ÷ 27 cubic yards, no compaction allowance — sand is screeded, not compacted.
- Excavation depth = base + sand + paver thickness + 1″ for the edge restraint.
Worked example
A 20 × 14 ft patio, 4″ base, 1″ sand, 2⅜″ pavers:
- Area = 280 sq ft
- Base compacted = 280 × 0.333 = 93.3 cu ft = 3.46 cu yd; order 4.7 cu yd loose
- Sand = 280 × 0.0833 = 23.3 cu ft = 0.86 cu yd
- Excavation = 4 + 1 + 2.375 + 1 = 8.4″, or 195 cu ft of spoil
That spoil is 7.2 cubic yards of dirt to get rid of — roughly a small dumpster or two pickup loads. It is the line item everyone forgets, and it costs as much as the gravel.
Why the base is specified compacted
Every published base depth for pavers refers to the compacted thickness, usually 4 inches for pedestrian traffic and 6–8 for vehicles. Loose stone at 4 inches compacts to under 3, and a patio on 3 inches of base will settle unevenly within two winters.
Compaction is done in lifts of 2 inches with a plate compactor, watered between passes. Dumping 8 inches and compacting once leaves the bottom loose, which is where the settlement starts.
Where the base fails anyway
- It does not assess the subgrade. Clay needs a geotextile separator and sometimes a deeper base; sand may need none.
- It does not include edge restraint, which is essential and priced per linear foot.
- It does not size a drainage slope. A patio needs about 1% fall away from the house; see patio slope.
- It does not count pavers, which is the paver calculator.
Questions people actually ask
How much gravel goes under a paver patio?
Four inches compacted for foot traffic, six to eight for vehicles. Order about 35% more than the compacted volume, because crushed stone loses roughly a third of its loose depth under compaction.
How deep do I excavate for a paver patio?
Base plus sand plus paver thickness plus an inch. For a 4-inch base, 1-inch sand and a 2⅜-inch paver, that is 8⅜ inches.
Can I use sand instead of gravel for the base?
No. Sand does not compact into a stable layer and migrates when wet. The base is crushed stone; sand is only the 1-inch bedding layer that the pavers sit on.
How much does a patio base cost?
Crushed aggregate runs $30–50 per cubic yard delivered, so a 280 square foot patio with a 4-inch base is roughly $180–250 in stone, plus $80–120 in sand and the compaction rental.