Gravel Calculator

Frequently Asked Questions About Calculating Gravel

Q1. How much gravel do I need?

To find how much gravel you need, multiply the area’s length and width in feet by the depth in feet (divide inches by 12) to get cubic feet, then divide by 27 for cubic yards. Gravel is often sold by the ton, and one cubic yard weighs roughly 1.4 tons, so multiply your cubic yards by about 1.4 to estimate tonnage. For example, a 20 ft x 10 ft area at 4 inches deep is about 2.5 cubic yards, or roughly 3.5 tons. Our Gravel Calculator gives cubic yards and tons.

Q2. What size gravel is best for a driveway?

A driveway is best built in layers with different gravel sizes: a base of larger 2 to 3 inch crushed stone (often called #2 or clean stone), a middle layer of #57 stone (about 3/4 inch), and a top surface of smaller crushed stone with stone dust (#411 or ‘crusher run’) that compacts into a firm surface. Pea gravel looks attractive but shifts underfoot and isn’t ideal as a driving surface. The layered approach gives drainage, stability, and a smooth finish that holds up to traffic.

Q3. How deep should a gravel driveway or path be?

For a gravel driveway, install a total depth of about 4 to 6 inches, ideally in layers: a coarse base layer topped by smaller gravel for the surface. Walkways and garden paths need only 2 to 3 inches over a stable base. For areas carrying heavy vehicles, go deeper—up to 8 to 12 inches across multiple layers. A landscape fabric underlayment helps prevent the gravel from sinking into the soil. Deeper installs need much more material, so confirm depth before calculating.

Q4. Do I need landscape fabric under gravel?

Landscape fabric (geotextile) under gravel is highly recommended for driveways and paths because it separates the gravel from the soil below, preventing the stone from sinking into mud over time and helping suppress weeds growing up through the surface. A woven geotextile fabric is more durable for driveways carrying weight, while lighter fabric suits decorative gravel areas. The fabric also improves load distribution and stability. Skipping it often leads to gravel disappearing into the ground and needing frequent topping up.

Q5. How do I keep gravel from spreading or migrating?

Edging is the key to containing gravel—metal, plastic, stone, brick, or timber borders along the sides keep the stone from spreading into lawns and beds. For driveways, a sturdy edge restraint plus proper depth and compaction holds the surface in place. Gravel stabilizer grids (honeycomb panels) lock stone in place on slopes and high-traffic areas, reducing ruts and migration. Choosing angular crushed stone over smooth rounded pea gravel also helps, since angular pieces interlock and shift less.