Planning a Gravel Driveway: Depth and Coverage

Gravel is sold by the ton, and delivery trucks dump the full load whether you have room for it or not. Over-ordering by three or four tons means finding a place to store loose stone or paying dump fees to haul it away. Under-ordering leaves your driveway half-finished with a visible seam between old and new gravel that never compacts uniformly.

Depth is the variable most homeowners get wrong. Two inches of gravel over dirt washes away in the first hard rain. Four to six inches over a properly compacted base creates a surface that supports passenger vehicles year-round. The tonnage difference between 2 inches and 6 inches on a 50-foot driveway is substantial — and so is the performance gap.

Gravel type matters as much as quantity. Round river rock looks attractive but rolls under tire pressure. Angular crushed stone with fines locks together when compacted and forms a stable driving surface. Planning your layers — base stone, middle course, and top dressing — affects both total tonnage and long-term durability.

Walk the driveway path and note slope, existing soil type, and drainage patterns. Water must flow off the driveway surface, not pool in low spots. A minimum crown of 2 percent (quarter inch per foot) or a consistent side slope directs runoff to ditches or swales.

Mark the driveway edges with stakes and string. Measure total length and average width at three points — entrance, middle, and end — and use the average width for calculations. A driveway that flares at the road needs the flared section measured separately and added to the total.

Remove topsoil, organic matter, and soft spots before placing gravel. Excavate 6 to 8 inches below finished grade to make room for the base layer plus surface gravel. Skipping excavation is the number one reason gravel driveways fail within two years.

The base layer uses larger crushed stone — typically 2 to 3 inches in diameter, often called #2 or #3 stone. Install 4 to 6 inches of base material over geotextile fabric on clay soils to prevent the stone from sinking into mud.

Compact the base with a plate compactor or roller in 2-inch lifts. Each lift must be compacted before the next goes down. An uncompacted base settles unevenly and telegraphs bumps through the surface gravel within months.

Calculate base volume separately from surface gravel. A 100-foot driveway, 10 feet wide, with 4 inches of base is 100 × 10 × 0.333 = 333 cubic feet, or 12.3 cubic yards. At roughly 1.4 tons per cubic yard for crushed stone, that is about 17 tons of base material.

The driving surface uses smaller crushed stone with fines — often called crusher run, road base, or 57 stone topped with 78 stone. The fines fill voids and bind the surface when compacted. Plan 3 to 4 inches of surface gravel over the compacted base.

For heavy use — daily truck traffic, RV parking, or steep grades — increase surface depth to 4 to 6 inches. Light foot-traffic paths need only 2 to 3 inches over a base and can use pea gravel or decorative stone. See our gravel depth guide for depth recommendations by use case.

Calculate surface volume the same way: length × width × depth in feet, divided by 27 for cubic yards, multiplied by material density for tons. Add 10 percent for compaction loss and spillage during spreading.

Suppliers quote and deliver by the ton, not cubic yard. Crushed limestone and granite weigh approximately 1.4 to 1.6 tons per cubic yard depending on moisture content. Pea gravel runs lighter at about 1.3 tons per cubic yard.

Ask your supplier for the specific weight of the product you are buying. A 0.1 ton-per-yard difference adds up on a 20-ton order. Multiply cubic yards by the supplier's conversion factor to get tonnage.

Delivery trucks carry 10 to 20 tons depending on size. Split large orders across multiple deliveries if your staging area cannot hold the full quantity. Have the dump location marked with cones or flags before the truck arrives.

Spread gravel in lifts no thicker than 4 inches and compact each lift. Rake to crown before compacting so water sheds properly. A plate compactor works for most residential driveways; rent a roller for long driveways over 200 feet.

Install edging — steel, plastic, or concrete — to keep gravel from migrating into lawn and beds. Without edging, you will rake stone back from the yard every spring indefinitely.

Plan to top-dress with one to two tons every one to two years as fine material washes away and stone works into the base. Keeping extra gravel on hand in a dry corner of the yard makes annual maintenance a half-day job instead of a full reorder and delivery.

• Spreading gravel directly on topsoil without excavation or geotextile fabric, causing the stone to sink into mud within months.
• Using round river rock as a driving surface — it rolls and ruts under tires instead of locking together.
• Calculating volume in inches without converting to feet, overstating material need by 12 times.
• Skipping compaction between lifts, resulting in a spongy surface that settles unevenly after the first rain.
• Forgetting to account for the flared entrance area where the driveway meets the road, under-ordering by several tons.
• Ordering all material as one stone size instead of planning separate base and surface layers with appropriate aggregate.