How to Calculate Stone for Landscaping and Driveways
Calculating the amount of crushed stone, river rock, or gravel needed for a project involves finding the total cubic volume of the area and converting it into tons. While some lighter materials like mulch are sold by the yard, aggregates and heavy stones are almost universally priced and delivered by the ton.
- L = Area Length (in feet)
- W = Area Width (in feet)
- D = Desired Depth (in inches)
Note: A standard conversion factor for regular crushed stone or gravel is 1.4 tons per cubic yard (approx. 2,800 lbs). Highly dense or wet materials may weigh slightly more.
If you are planning to buy bagged stone from a local home improvement store, note that standard bags typically contain 0.5 cubic feet. Because 1 cubic yard equals 27 cubic feet, it takes roughly 54 bags to equal a single cubic yard.
| Stone Depth | Coverage Area (Square Feet) | Common Application |
|---|---|---|
| 2 inches | ~115 sq ft | Light pathways and decorative garden beds. |
| 3 inches | ~77 sq ft | Standard patios and heavy foot-traffic areas. |
| 4 inches | ~57 sq ft | Standard residential driveways and parking pads. |
| 6 inches | ~38 sq ft | Heavy vehicle driveways or soft subgrade bases. |
Frequently Asked Questions
How much does a cubic yard of stone weigh?
A standard cubic yard of dry crushed stone or gravel typically weighs about 2,800 pounds, which is 1.4 tons. Keep in mind that different types of stone have varying densities; for example, volcanic rock (scoria) is much lighter, while smooth river rock can be slightly heavier.
How deep should I lay decorative stone?
For standard garden beds and decorative landscaping over weed fabric, a depth of 2 to 3 inches is generally recommended. For driveways, a total depth of 4 to 6 inches is needed to provide adequate support and stability under the weight of vehicles.
Should I put landscape fabric under my stone?
Yes. Laying a heavy-duty, woven geotextile fabric beneath your stone is highly recommended. It serves two primary functions: it prevents weeds from growing up through the stones, and more importantly, it prevents the heavy rock from slowly sinking into the softer soil or mud beneath over time.