Gravel Calculator

Calculating gravel quantity comes down to three dimensions: length, width, and depth. Multiply these together to get volume in cubic feet, then divide by 27 (the number of cubic feet in a cubic yard) to convert to cubic yards — the unit bulk gravel is typically sold and delivered in. For example, a driveway that is 40 feet long, 12 feet wide, and 4 inches (0.333 feet) deep requires 40 × 12 × 0.333 = 159.84 cubic feet, or about 5.9 cubic yards. Suppliers sell in whole or half cubic yards, so you'd order 6 cubic yards.

Gravel is also sold by weight — typically in short tons (2,000 pounds each). The conversion from volume to weight depends on the density of the specific material. Crushed limestone runs about 1.5 tons per cubic yard, while lighter materials like lava rock weigh only about 0.65 tons per cubic yard. Getting the density right is important: a 6-cubic-yard order of crushed stone weighs roughly 9 tons, which may require a heavy-duty delivery truck, whereas the same volume of lava rock weighs only about 3.9 tons.

For small jobs where bulk delivery isn't economical, gravel is also available in 50-pound bags at home improvement stores. The calculator converts your total weight to the number of bags needed. One 50-pound bag of pea gravel covers roughly 0.5 cubic feet at a 2-inch depth, so small decorative projects can often be completed with a dozen bags without needing a bulk delivery. For anything over about 1 cubic yard, bulk is almost always more economical per ton.

Crushed stone and limestone are the most common gravel materials for driveways and base layers. With a density of around 1.5 tons per cubic yard, they're among the heavier options. Crushed stone locks together well when compacted, making it ideal for driveways, parking areas, and structural base applications. Limestone specifically is also used in drainage because it doesn't break down quickly in wet conditions. Angular crushed stone packs tighter than rounded stone, reducing shifting and rutting under vehicle traffic.

Pea gravel and river rock are smooth, rounded stones typically ¼ to ¾ inch in diameter. They weigh about 1.35 tons per cubic yard and are popular for garden paths, playgrounds, dog runs, and decorative landscape applications. Because they're rounded, they don't lock together as well as angular crush — they shift under foot traffic and vehicle weight — so they're not recommended for driveways without an edging system to keep them contained. Their smooth texture makes them comfortable underfoot and visually appealing in ornamental beds.

Lava rock is the lightest common landscape gravel at roughly 0.65 tons per cubic yard — less than half the weight of crushed stone. It's popular in xeriscaping and drought-tolerant gardens because its porous surface retains some moisture and insulates plant roots. The dark reddish-brown color contrasts well with light-colored plantings. However, lava rock is much more expensive per cubic yard than crushed stone or pea gravel, and it can be sharp-edged, making it less suitable for barefoot areas or pet-friendly spaces.

The right gravel depth depends on what the surface will be used for. For decorative garden paths and flower bed borders, 2 inches of gravel is typically sufficient to suppress weeds and provide a clean aesthetic. At this depth, a ton of pea gravel covers roughly 150 square feet — enough for a substantial garden path. Adding a landscape fabric layer underneath significantly extends the weed-suppression effectiveness without adding to the gravel quantity needed.

Driveways require more material: 4 inches of compacted gravel is the minimum for light vehicle traffic, while 6 inches is recommended for areas with heavy trucks, delivery vehicles, or frequent use. A 4-inch layer provides enough depth to distribute the vehicle's weight without the gravel punching through into soft soil below. For long driveways, consider a base layer of larger crushed stone (1.5 to 2 inches) topped with a finer ¾-inch layer that packs well and provides a stable driving surface.

Drainage applications like French drains, dry creek beds, and gravel-filled trenches typically use 6 to 12 inches of washed crushed stone or gravel, depending on the volume of water to be managed. For septic system leach fields, specific gravel sizes (typically ¾-inch washed stone) and depths (12 to 18 inches) are specified by local codes. Always check local requirements for drainage and septic installations before ordering material, as undersizing a drainage application can cause waterlogging and expensive repairs.

Bulk gravel — delivered by the ton or cubic yard on a dump truck — is significantly cheaper per unit than bagged gravel. At most suppliers, bulk crushed stone runs $20–$50 per ton before delivery, while a 50-pound bag at a home improvement store costs $5–$8, which works out to $200–$320 per ton. For any project requiring more than 1 cubic yard (roughly 1.35–1.5 tons for most stone types), bulk is almost always more economical. Delivery minimums vary by supplier, but most require at least 1–2 cubic yards or 1–2 tons per order.

Logistics are the main reason people choose bags over bulk for small projects. A dump truck delivery requires a wide, accessible driveway or staging area, and the load is deposited in one spot — you then need to move it by wheelbarrow. If your project is in a tight backyard, on a steep slope, or in a location with limited access, the physical labor of relocating a bulk delivery can offset the cost savings. Bagged gravel can be carried by hand and deposited exactly where needed, making it practical for raised beds, small garden patches, or any location with restricted access.

When estimating costs, include delivery charges in the comparison. Many bulk suppliers charge $50–$150 for delivery, depending on distance. At those rates, a small bulk order (2–3 yards) may still come out cheaper than bags for the same quantity, or it may break even. Get delivery quotes before ordering, especially for projects on the margin between bag and bulk. Also consider that some suppliers have price breaks at 5, 10, or 20-ton quantities for larger projects like full driveway installations.

Proper site preparation before laying gravel dramatically improves the longevity and appearance of the finished surface. Start by clearing the area of all vegetation, roots, and organic matter. Existing grass can be killed with a non-selective herbicide or removed by sod cutting. Level the surface to eliminate high spots and fill in any low areas — gravel will follow the contour of whatever is beneath it, so significant irregularities will show through. For driveways, excavate to a consistent depth (usually 6–8 inches to accommodate both base and top layers) and compact the subgrade soil with a plate compactor before adding any gravel.

Landscape fabric (also called geotextile or weed barrier) between the soil and the gravel layer serves two purposes: it suppresses weed growth, and it prevents the gravel from migrating down into the soil over time, especially in sandy or loose subgrades. Use heavy-duty commercial-grade fabric (3–4 oz/yd²), not the thin decorative fabric sold for garden beds — the heavier material won't break down as quickly and holds up better under traffic. Overlap seams by at least 6 inches and secure edges with landscape fabric staples before adding gravel. Some drainage applications intentionally omit fabric to allow water to percolate freely into the soil.

Install edging — metal landscape edging, plastic edging, treated lumber, or bender board — along all exposed edges of the gravel area before laying the material. Edging keeps gravel from spreading into lawns and garden beds, maintains a clean visual line, and greatly reduces ongoing maintenance. Once edging is in place, spread gravel from the centre outward using a rake, working in manageable sections. For driveways, apply in two or three layers, compacting each layer with a plate compactor before adding the next. The final pass should use a rake to achieve a uniform surface depth and a smooth texture.