The base is the patio
Pavers are only as flat as what is under them. The standard build-up is: 4–6 inches of compacted ¾-inch crushed stone, a 1-inch screeded bedding sand layer, then the pavers. Walkways can live with 4 inches of base; a driveway needs 8–12 inches. The calculator assumes you enter the stone depth you plan to compact — order 10–20% extra because crushed stone loses real depth when the plate compactor goes over it.
Two lifts, not one dump
More than 4 inches of stone in a single lift never compacts properly — the top crusts over while the bottom stays loose. Professional practice is two lifts of 2–3 inches, each wetted and compacted with a plate compactor until the screed rails read true.
Geotextile is cheap insurance
On clay or silty soil, lay a non-woven geotextile fabric between the dirt and the stone. It stops the base from punching into the subgrade over the years — a $40 roll versus re-laying the patio in season three.
Base depth is set by the load, not by the paver
Pavers are the visible layer, but the base is what carries the load, drains the water and decides whether the surface stays flat in five years. Get the base wrong and no amount of premium stone saves the job: the pavers will settle, rock and rut from the first freeze-thaw cycle.
Base depth is set by what will travel on the surface, not by the paver thickness:
| Use | Compacted base | Bedding sand |
|---|---|---|
| Patio, walkway, foot traffic | 4 in | 1 in |
| Driveway, cars and light vehicles | 6 in | 1 in |
| Driveway, heavy or commercial | 8–12 in | 1 in |
Two adjustments matter in practice. On clay soils add about 2 in, because clay holds water and moves when it freezes. In a cold climate with deep freeze-thaw, add another 2–4 in. Note that the local frost line is a design input, not the answer itself — it tells you how deep freezing reaches, which is not the same as the aggregate thickness you should order.
How much base material to order
Two conversions get you from a patio drawing to a delivery ticket:
- Volume:
cubic feet = area (sq ft) × depth (in) ÷ 12, thencubic yards = cubic feet ÷ 27 - Weight:
tons = cubic yards × 1.5— crushed stone runs about 1.5 short tons per cubic yard
The division by 12 is where most ordering mistakes happen: 4 inches is 0.333 feet, not 4.
| Project | Base volume | Weight |
|---|---|---|
| 12 × 12 ft patio, 144 sq ft at 4 in | 48 cu ft = 1.78 cu yd | ~2.7 tons |
| 12 × 24 ft driveway, 288 sq ft at 6 in | 144 cu ft = 5.33 cu yd | ~8.0 tons |
| 20 × 20 ft driveway, 400 sq ft at 6 in | 200 cu ft = 7.41 cu yd | ~11.1 tons |
Note how quickly the numbers climb. Doubling the depth doubles the tonnage, and moving from a patio to a driveway adds half again as much depth — which is why the base, not the pavers, is usually the largest line on the material order.
Which base material to use
| Material | Best for | Watch for |
|---|---|---|
| #57 crushed stone (about 3/4 in, clean) | Standard paver base; drains freely | Does not compact into a plate, so it needs restraint at the edges |
| Crusher run / road base (with fines) | Driveways and any loaded surface — compacts to a hard plate | Holds water unless drained; needs a slope |
| Recycled concrete | Budget base where drainage is adequate | Variable grading; check for metal and debris |
| 3/4 in clean gravel | Drainage layer below a crusher-run base | Not a finish base on its own — it stays loose |
For a patio, #57 over compacted subgrade is the common choice. For a driveway, a crusher-run base is usually the better call because it compacts into a stiff plate that spreads wheel loads instead of letting the pavers rock.
Compaction: lifts, not one pass
This is the step most DIY jobs skip, and it is the one that decides whether the surface stays flat.
- Place in lifts of about 2 in, and compact each lift before adding the next. A single 6 in layer cannot be compacted through its full depth — the plate compactor only works the top couple of inches.
- Water lightly before compacting crusher-run material. Moisture helps the fines bind and the material reach density.
- Compact the subgrade too, before any stone goes down, and remove soft spots rather than bridging them.
- Compact in two directions on each lift so the material does not creep in one direction.
- Compact the finished pavers once more after laying and before joint sand, to seat them into the bedding layer.
Hand tampers work for a walkway. For anything a vehicle touches, a plate compactor is not optional — the density difference between a hand-tamped and a machine-compacted base is exactly the difference between a flat driveway and a rutted one.
Bedding sand on top, and the three things people forget
The bedding layer is 1 in of coarse sand, screeded level, and its volume is simply area divided by 324 (that constant is 12 in × 27, doing both conversions at once).
- 12 × 12 ft patio: 144 ÷ 324 = 0.44 cu yd, about 24 bags of 50 lb
- 12 × 24 ft driveway: 288 ÷ 324 = 0.89 cu yd, about 48 bags
Then the three items that are routinely left off the order:
- Joint sand. Polymeric sand sets when watered and resists wash-out. Coverage is set by joint width: a 50 lb bag covers roughly 90–120 sq ft at 1/8 in joints, falling to 40–60 sq ft at 1/4 in.
- Edge restraint. Every paver surface spreads outward under load, and freeze-thaw accelerates it. Restraint is required on all installations, not just driveways.
- Geotextile fabric over soft or clay subgrade, to stop the stone sinking into the soil.
Common mistakes
- Ordering base by area instead of volume. Depth is what you are buying, and it is the term people drop.
- Confusing inches and feet. Entering 6 for a 6 in depth instead of 0.5 ft multiplies the order by twelve.
- Compacting in one thick layer. The lower half stays loose and the surface settles.
- Skipping the subgrade. A soft spot under the base becomes a dip in the finished surface.
- Using clean stone under a driveway. #57 does not compact into a load-spreading plate; crusher run does.
- Forgetting drainage. A base that holds water — crusher run with no fall — turns into a freeze-thaw problem every winter.
- Leaving edge restraint off the order. It is a requirement, and it is the item most often discovered missing at the end of the job.
- Assuming volume equals weight. Suppliers sell by the cubic yard, by the ton or by the bag — know which unit your invoice uses before ordering.
Tools for building and compacting the base
The base is the part of a paver job that is invisible when it is finished and obvious when it is wrong. These are the items the depth and compaction figures on this page assume.
- Plate compactor — Place the base in 2-inch lifts and compact each one. A hand tamper cannot reach the density a driveway base needs, and a single thick layer stays loose underneath.
- Non-woven geotextile fabric — Laid over clay or silt subgrade before the stone goes down. It stops the base sinking into the soil and costs far less than the extra stone it saves.
- Wheelbarrow — Several tons of base does not move itself. Check for a pneumatic tyre — solid tyres sink in loose stone.
- Steel bow rake — For spreading and levelling each lift to depth before compacting. A garden rake clogs and bends on aggregate.
As an Amazon Associate I earn from qualifying purchases. The links above are affiliate links — if you buy through one, the price you pay is unchanged and a small commission helps keep these calculators free. Tools are listed because the job calls for them, not because of commission rates.
Sources and standards
Where these figures come from
Every number on this page is taken from the reference material below rather than from memory. Where a value changes with a game or platform update, the page says so and tells you where to check it.
- Interlocking Concrete Pavement Institute (ICPI) — base depth by application, compaction requirements and edge restraint standards.
- National Stone, Sand & Gravel Association — aggregate grading and the working density of crushed stone (about 1.5 short tons per cubic yard).
- ASHRAE — freeze-thaw design conditions used for the cold-climate base adjustments.
Figures, formulas and reference tables last verified: 24 September 2026