How deep should gravel be?
Depth by job, layer by layer: driveways, paths, patios, paver base and drainage.
The short answer
4 inches of gravel for a residential driveway (6–8 in two layers if trucks use it), 2–3 inches for a footpath or bed, 4–6 inches of compacted base under pavers (up to 12 in freezing climates or under a drive), 12 inches of washed stone around a French drain pipe, and 3–4 inches for a dog run or play area.
- 4″ depth Driveway Residential, on good base
- 2–3″ depth Paths & beds Foot traffic only
- 4–6″ compacted Paver base 8–12″ where it freezes
- 12″ stone French drain Around the pipe
- 3–4″ depth Dog run Pea gravel or DG
- 2″ depth Top-up layer Refreshing existing stone
How deep gravel should be depends on what will drive, walk or drain through it. A garden path needs two inches. A driveway that takes a delivery truck needs eight, in two different materials. Getting this wrong is expensive in both directions: too shallow and the stone works into the soil and ruts within a season, too deep and you have paid for material that does nothing.
The depths below are finished, compacted depths: what you want when the job is done. Because dense-graded stone loses roughly 20–25% of its loose volume under a plate compactor, you order more than this. Every calculator on this site adds that allowance for you.
Gravel depth by project
| Project | Depth | Material | Notes |
|---|---|---|---|
| Residential driveway (cars) | 4″ | Road base, or base + 1″ topping | Over compacted subgrade and fabric |
| Driveway (trucks, RV, farm) | 6–8″ | 4″ base + 2–4″ surface stone | Two layers, compacted separately |
| Driveway on soft or clay soil | 8–12″ | Base + geotextile fabric | Fabric is not optional here |
| Garden or utility path | 2–3″ | Pea gravel, DG, 3/8″ stone | Needs edging or it migrates |
| Patio surface (loose stone) | 3″ | Pea gravel or DG over base | Over 2″ of compacted base |
| Paver / flagstone base | 4–6″ | Road base or 3/4″ minus | 8–12″ in freeze-thaw climates |
| Paver base under a driveway | 8–12″ | Road base, compacted in lifts | Plus 1″ of bedding sand |
| French drain | 12″ | #57 washed stone | Around the pipe, wrapped in fabric |
| Foundation / footing drain | 12–18″ | #57 washed stone | Above and around the pipe |
| Dry well | 24–36″ | #57 washed stone | Sized to the runoff volume |
| Dog run | 3–4″ | Pea gravel over base | Rounded stone only, for paws |
| Playground surfacing | 9–12″ | Pea gravel or rubber mulch | Fall-height driven; check ASTM F1292 |
| Shed or slab sub-base | 4–6″ | Road base, compacted | Under the vapour barrier |
| Fire pit base | 4–6″ | Crushed stone | Drains and prevents heat spalling |
| Refresh an existing surface | 1–2″ | Same as original surface stone | Rake and compact into what is there |
Why depth matters more than material
A gravel surface does not work by being hard. It works by spreading a load over enough subgrade area that the soil beneath can carry it. The deeper the layer, the wider the cone of pressure at the bottom, and the less stress lands on any one square inch of soil.
That is why a driveway on sand can get away with four inches while the same driveway on wet clay needs eight to twelve. It is not the stone that failed in a rutted driveway; it is the soil under it, pumping up through a layer too thin to protect it. Adding geotextile fabric between soil and stone is the other half of the answer: it stops the two mixing, which is what actually destroys a thin gravel layer over time.
Building it in layers
Anything over about four inches should go down in lifts: layers of three to four inches, each compacted before the next goes on. A plate compactor cannot densify eight inches of loose stone in one pass; the top compacts, the bottom stays loose, and the surface settles unevenly in the first wet month.
- Excavate to the full finished depth plus any topsoil you are stripping, and grade for drainage: a crown or a 1–2% fall.
- Compact the subgrade. Stone laid on loose soil settles into it no matter how deep it is.
- Lay geotextile fabric over the subgrade. On clay or anywhere that stays wet, this is the single highest-value thing on the list.
- First lift: 3–4″ of dense-graded base, raked level, then compacted with a plate compactor or roller. Dampen it: dry stone will not compact.
- Second lift: another 3–4″ if the design calls for it, compacted the same way.
- Surface layer: 1–2″ of the stone you actually want to look at, raked but only lightly compacted.
The gravel driveway calculator handles the two-layer build directly, and the paver base calculator does base plus bedding sand for a paver install.
What each depth costs you in material
Depth is the most expensive variable in the whole job, because it multiplies straight through. Doubling the depth doubles the material. Here is what one cubic yard covers at each of the common depths:
| Depth | ft² per yd³ | ft² per ton of gravel | yd³ for 500 ft² |
|---|---|---|---|
| 1″ | 324 | 231 | 1.54 |
| 2″ | 162 | 116 | 3.09 |
| 3″ | 108 | 77 | 4.63 |
| 4″ | 81 | 58 | 6.17 |
| 6″ | 54 | 39 | 9.26 |
| 8″ | 41 | 29 | 12.35 |
| 12″ | 27 | 19 | 18.52 |
The jump from 4 to 6 inches on a 600 square foot driveway is 3.7 extra cubic yards, over five tons of stone and a few hundred dollars. Worth it if trucks use the drive or the soil is poor; wasted if neither is true.
The five depth mistakes
- Spreading a driveway's worth of stone in one lift. It will look right and settle into ruts by the second wet month.
- Skipping the fabric on clay. Stone and clay will mix, and once mixed the layer has no structural depth left at all.
- Using rounded stone as a base. Pea gravel and river rock never lock together: they roll. Bases need angular, dense-graded stone with fines.
- Ordering the finished depth. Compacted base loses 20–25% of its loose volume, so ordering the finished figure leaves you short.
- Deep loose gravel as a walking surface. Anything over about 3 inches of loose stone is unpleasant to walk on and impossible to push a wheelbarrow through.
Once you have settled on a depth, the gravel calculator turns it into cubic yards, tons and a delivered cost, with the compaction allowance included. If your supplier has quoted a per-ton price, the cubic yards to tons guide converts between the two.
Last reviewed 2026-09-07. Figures here are typical ranges, not a quote: if a local supplier gives you a number for their product, use theirs. Something wrong? Email hello@bulkmaterialcalculator.com.