About this calculator
A paver patio is three layers: a compacted gravel base, a thin bed of sand and the pavers themselves. This calculator estimates all three — the number of pavers for your layout, the tons of base aggregate and sand to order, and the length of edge restraint to hold it together.
Pavers are laid tight with sand swept into the hairline joints, so the count is simply patio area divided by paver area, plus an allowance for cuts.
How to use it
- Enter the patio length and width. For L-shapes, run the calculator for each rectangle and add the results.
- Enter the paver size printed on the product (for example 4 × 8 in, 6 × 9 in or 12 × 12 in).
- Set the waste allowance: 5–10% for straight patterns, 15% for herringbone, diagonal layouts or curved edges.
- Enter the base depth (4 in for foot traffic, 6–8 in for driveways) and sand depth (1 in).
The formula
Pavers = area ÷ (paver length × paver width) × (1 + extra%)
Base gravel = area × base depth × 1.15 (compaction)
Bedding sand = area × sand depth
Weight = volume × density (base 1.5, sand 1.35 tons per cu yd)
Loose gravel compacts by roughly 15% when you run a plate compactor over it, so the calculator orders that much extra base. Densities are typical figures for crusher run and dry concrete sand; your supplier’s numbers may differ slightly.
Worked example
These are the calculator’s starting values and the results they produce:
| Patio length | 12 ft |
|---|---|
| Patio width | 12 ft |
| Paver length | 8 in |
| Paver width | 4 in |
| Extra for cuts and breakage | 10 % |
| Gravel base depth | 4 in |
| Bedding sand depth | 1 in |
Tips before you buy
- Excavate to the base depth plus the sand bed plus the paver thickness, and slope the subgrade about ¼ in per foot away from the house.
- Compact the base in 2 in lifts; a single deep layer never compacts fully.
- Order pavers by the pallet if you can — partial pallets often cost more per paver.
- Sweep polymeric sand into the joints after installation to lock pavers and discourage weeds.
Frequently asked questions
How many pavers do I need for a 12×12 patio?
A 12 × 12 ft patio is 144 sq ft. With standard 4 × 8 in pavers (4.5 per square foot) that is 648 pavers, or 713 with 10% extra for cuts.
How much gravel do I need under pavers?
Plan on 4 in of compacted base for patios and walkways. For a 144 sq ft patio that is about 2 cubic yards of loose base once you allow for compaction — roughly 3 tons.
How much sand goes under pavers?
A 1 in screeded bed of coarse concrete sand is standard. That is about 0.44 cubic yards per 144 sq ft.