3-Layer Gravel Driveway Calculator
Enter the driveway size and surface stone. Layer depths, prices and fabric are below.
Driveways & Paving
Gravel Driveway Calculator
Quick answer: tons per layer = area × (depth in ÷ 12) ÷ 27 × (1 + compaction %) × 1.4. A 12 × 100 ft drive built with 4 in of #3, 4 in of #57 and 2 in of crusher run needs about 55.5 tons — 21.8 + 21.8 + 11.9 tons, or five 14-ton loads.
Estimate a new gravel driveway layer by layer: sub-base, base and surface stone in tons and cubic yards, the geotextile fabric under it, truckloads per stone type, and what the stone costs per layer and per square foot.
Three-layer driveway section
How to calculate a layered gravel driveway
Each layer is a separate order of a different stone, so the math runs three times over the same footprint. The only things that change between layers are compacted depth, how much the stone shrinks when rolled, its weight per cubic yard, and its price.
A × (d ÷ 12) ÷ 27 × (1 + c) × ρ
= tons for one layer (A = area in ft², d = compacted depth in inches, c = compaction allowance, ρ = tons per yd³)
- Find the area: length × width, plus any turnaround, parking pad or apron as extra square feet.
- Pick each layer's compacted depth — the thickness after rolling, which is how plans and contractors specify it.
- Convert to cubic yards: area × depth ÷ 12 ÷ 27.
- Add the compaction allowance: about 15% for crusher run or #411, about 5% for clean stone such as #3, #57 or pea gravel.
- Weigh it: × 1.4 tons per cubic yard, a common figure for crushed stone. Ask the quarry for its own number.
- Count loads per layer (tons ÷ truck capacity, rounded up), because each stone type arrives on its own truck.
- Price it: tons × $/ton per layer; total ÷ area gives cost per ft².
Worked example: 12 × 100 ft rural drive
A 1,200 ft² single-lane drive from a county road to a house, built 4 in of #3, 4 in of #57 and 2 in of crusher run, at 1.4 tons/yd³, with $40, $45 and $45 per ton.
- Sub-base: 1,200 × 4 ÷ 12 = 400 ft³ = 14.81 yd³; × 1.05 = 15.56 yd³ = 21.78 tons → 2 loads, $871
- Base: same depth and allowance = 21.78 tons → 2 loads, $980
- Surface: 200 ft³ = 7.41 yd³; × 1.15 = 8.52 yd³ = 11.93 tons → 1 load, $537
- Total: 55.48 tons (39.63 loose yd³), 5 truckloads, $2,388 in stone, about $1.99 per ft²
- Fabric: 1,200 ft² × 1.10 = 1,320 ft² of woven geotextile
Tons per 100 ft of 12 ft driveway, by layer depth
1,200 ft² at 1.4 tons/yd³. Use the 5% column for clean stone and the 15% column for crusher run or #411; add the rows for each layer you plan. Loads are 14-ton trucks at the 15% figure.
| Compacted depth | In-place yd³ | Tons, +5% (clean stone) | Tons, +15% (crusher run) | 14-ton loads |
|---|---|---|---|---|
| 2 in | 7.41 | 10.9 | 11.9 | 1 |
| 3 in | 11.11 | 16.3 | 17.9 | 2 |
| 4 in | 14.81 | 21.8 | 23.9 | 2 |
| 6 in | 22.22 | 32.7 | 35.8 | 3 |
| 8 in | 29.63 | 43.6 | 47.7 | 4 |
| 10 in | 37.04 | 54.4 | 59.6 | 5 |
| 12 in | 44.44 | 65.3 | 71.6 | 6 |
Why three layers beat one thick layer
One stone cannot do every job. Large clean stone at the bottom interlocks into a stiff platform that spreads wheel loads over soft subgrade, but it is too coarse to drive on. A middle layer chokes the voids of the big stone and adds drainage. The top layer needs fines so it packs into a tight, smooth crust that sheds water. A single thick dump of crusher run tends to pump mud up from below; a single layer of clean stone never firms up and ruts.
How deep for your soil
Treat these as starting points, not an engineered design. On firm, sandy or gravelly ground that drains well, 6–8 in of total stone often holds up for cars. On clay, silty or wet ground, many builders go to 12 in or more, mostly by thickening the sub-base, and lay woven geotextile on the subgrade first. If a loaded pickup leaves deep ruts in the bare subgrade, dig out the soft spots or ask a local contractor before adding stone.
Crown it so water leaves
A side slope of about ¼–½ in per foot from the centerline is commonly cited. On a 12 ft drive that is roughly 1.5–3 in higher at the center than at the edges. Shape the crown in the subgrade and in each layer, not just the surface, and give the water somewhere to go: a ditch, a swale or a culvert under the entrance.
Edging and maintenance
Without edges the surface stone migrates into the lawn. Steel or timber edging, a row of set stone, or simply a slightly raised grass shoulder keeps it in place. Rake the surface back toward the center after heavy rain, fill potholes with the same surface stone and tamp it, and plow with the blade raised or with skid shoes so it does not scrape the crown away.
Common layered-driveway mistakes
- Ordering by compacted depth only. 4 in of crusher run on the plan needs about 4.6 in of loose stone on the ground. Skipping the allowance is the most common reason a driveway ends up thin.
- Putting fines on the bottom. Crusher run as a sub-base over clay holds water against the soil. Keep the open, large stone low and the dense stone on top.
- Fabric without overlap. Separation fabric only works if seams overlap; 10% extra area is a reasonable allowance, and more on very soft ground or curved drives.
- Mixing up the stone names. #3, #4, #57 and #411 are common designations, but sizes and names vary by state and quarry. Ask for a gradation sheet.
- One truck for two stones. Different layers are usually separate deliveries. Plan where each pile goes so the truck can tip the base without driving on the finished sub-base.
- Skipping the plate compactor. Roll each layer before the next goes on; compacting 10 in of stone from the top does not reach the bottom.
Gravel driveway layers FAQ
What are the layers of a gravel driveway?
A common build is three layers: a sub-base of large clean stone such as #3 or #4, a base of #57 or crusher run, and a surface of crusher run or #411 that packs smooth. A typical starting point is 4 in + 4 in + 2 in, or 10 in of compacted stone in total.
How thick should a gravel driveway be on clay soil?
Soft or clay soil usually calls for more stone than firm ground: often 12 in or more in total, with a thicker sub-base and a woven geotextile on the subgrade. On firm, well-drained soil 6 to 8 in may hold up. These are rules of thumb; very wet or weak ground may need an engineer's or local contractor's advice.
How much crown should a gravel driveway have?
A side slope of about 1/4 to 1/2 in per foot from the centerline is commonly cited. On a 12 ft wide driveway that puts the center roughly 1.5 to 3 in higher than the edges. Too little crown lets water sit and form potholes; too much makes the stone wash to the sides.
How many truckloads of gravel for a 100 ft driveway?
A 12 × 100 ft driveway built 4 in + 4 in + 2 in at 1.4 tons per cubic yard takes about 55.5 tons with compaction allowance. Ordered by layer in 14-ton loads, that is 2 + 2 + 1 = 5 truckloads.
How much does a gravel driveway cost per square foot?
Stone alone for a 10 in three-layer build runs about $2 per sq ft at $40 to $45 per ton, the placeholder prices used on this page. Delivery, excavation, fabric, grading and labor are extra, and stone prices vary by region, so use your supplier's quotes for a real budget.
Why do you order extra gravel for compaction?
Stone is sold loose but measured in place after compaction. Dense-graded crusher run can lose about 15 percent or more of its volume under a roller, while clean stone such as #57 settles less, about 5 percent. Ordering by compacted depth alone leaves the layer thin.
How we built this calculator: results use the standard volume, area, and coverage formulas shown on this page, with typical U.S. material densities, bag yields, and waste factors that you can override. Written and checked by the YardsCalculator editorial team. Last reviewed: October 2026.
Last updated: October 9, 2026