Published August 13, 2026 · Updated August 23, 2026 · By Tupep
The base under a paver patio is the whole job. Pavers are just the surface you see. And the number that trips people up is that the depth you want finished is not the depth you order, because compacted aggregate ends up meaningfully thinner than the pile you dumped.
Three numbers, not one
A paver patio is three separate materials with three separate calculations:
- Compacted aggregate base. Dense-graded crushed stone with fines, compacted in lifts.
- Bedding sand. A thin screeded layer, usually 1 inch, that is never compacted before the pavers go down.
- Joint sand. Swept into the gaps after laying, a small quantity but a separate purchase.
Adding these together into one order is the most common mistake. They are different products and the base one carries a compaction allowance the others do not.
The formula
Loose cubic yards of base = (base footprint sq ft x compacted depth in inches / 324) x 1.25
The 324 is the constant every aggregate calc uses: a cubic yard covers 324 square feet one inch deep. The 1.25 is the compaction allowance, because dense-graded aggregate loses roughly 20 to 25 percent of its loose volume when it is properly compacted. If you order the finished depth, you finish an inch and a half low.
The footprint is bigger than the patio
Base has to extend past the paver edge, typically 6 inches on each open side, so the edge restraint has something solid to sit on and the perimeter pavers do not sink. That overdig adds up fast on a small patio.
For a 12 ft x 16 ft patio open on all four sides, we get: base footprint = 13 ft x 17 ft = 221 square feet, not 192. That is a 15 percent increase before you have calculated anything.
Worked example
Twelve by sixteen patio, foot traffic only, well-drained sandy subgrade, so we run a 6 inch compacted base.
- Base footprint: 13 x 17 = 221 sq ft
- Compacted volume: 221 x 6 / 324 = 4.09 cubic yards
- Loose order with the 1.25 allowance: 4.09 x 1.25 = 5.12 cubic yards
- At 1.40 tons per cubic yard for crusher run: 5.12 x 1.40 = 7.2 tons
Bedding sand, separately: 1 inch over the paver area only, 192 sq ft. 192 x 1 / 324 = 0.59 cubic yards, which at about 1.35 tons per cubic yard is 0.8 tons. Order 1 ton. Use concrete sand or a coarse washed sand, not mason sand, and no compaction allowance because this layer is screeded and left alone.
Joint sand: budget roughly 1 bag of polymeric sand per 75 to 100 square feet for standard pavers with tight joints, so 2 to 3 bags here. Wider joints or flagstone eat far more.
Base depth by application
| Application | Compacted base depth | Loose depth to place | Tons per 100 sq ft of footprint |
|---|---|---|---|
| Walkway, foot traffic | 4 in | 5 in | 2.2 |
| Patio, well-drained soil | 6 in | 7.5 in | 3.2 |
| Patio, clay soil or freeze-thaw climate | 8 in | 10 in | 4.3 |
| Driveway or parking area | 10 to 12 in | 12.5 to 15 in | 5.4 to 6.5 |
Why the 25 percent is not optional
Loose dense-graded aggregate is full of voids. A plate compactor collapses those voids and drives the fines into the gaps between larger stones. That is the entire point, because the interlocked mass is what carries load. The volume loss is the physical evidence that compaction happened. If your 6 inches of loose stone is still 6 inches after four passes, you did not compact it, you polished it.
Lifts and passes
| Compacted depth needed | Number of lifts | Loose thickness per lift |
|---|---|---|
| 4 in | 2 | 2.5 in |
| 6 in | 2 | 3.75 in |
| 8 in | 3 | 3.3 in |
| 12 in | 4 | 3.75 in |
Keep each loose lift under about 4 inches. A standard plate compactor only densifies the top few inches. Dump 8 inches loose and you get a hard crust over a soft middle, which settles later and telegraphs through the pavers as a dip you cannot fix without taking it apart.
Practical notes
- Dampen the aggregate lightly before compacting. Bone-dry stone will not knit. Soaking wet stone pumps and will not compact either.
- Check depth with a probe at several points, not just where you were standing. Base thickness varies more than you think across a patio.
- Slope the base at about 1/8 to 1/4 inch per foot away from the house. Build the slope into the base, not into the bedding sand.
- Bedding sand stays at a uniform 1 inch. Using it to correct base high and low spots is the classic shortcut, and it is exactly what causes waves two seasons later.
- Order the base a little long. Coming up half a yard short on the last lift means an extra delivery fee for almost no material.
Summary of the example order
| Material | Area used | Depth | Quantity to buy |
|---|---|---|---|
| Crusher run base | 221 sq ft | 6 in compacted | 5.12 cu yd / 7.2 tons |
| Concrete bedding sand | 192 sq ft | 1 in screeded | 0.6 cu yd / 1 ton |
| Polymeric joint sand | 192 sq ft | Joints only | 2 to 3 bags |
Related guides
- Driveway Slab Thickness and Volume
- Concrete for a 4×8 Patio
- How Much Concrete Per Fence Post
- Pea Gravel vs Crushed Stone
Sources and Further Reading
Run your own numbers with the Gravel Calculator, or browse every tool on the calculators index. Coverage figures and material constants are cross-checked against manufacturer technical data sheets before publication. See our Methodology page for how figures are selected and verified.
Planning estimate only. Results assume standard conditions and are intended for material planning. Verify against your product’s technical data sheet and your local building code before purchasing. Structural, electrical, and gas work should be specified by a licensed professional.
Last updated: August 23, 2026
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