What is the density of river rock?

River rock (smooth, rounded natural stone) has a typical bulk density of around 1,682 kg/m³ (105 lb/ft³). Exact density varies slightly with rock size and how tightly the stones pack together; this calculator uses 1,682 kg/m³ as the standard value, with adjusted densities for smaller and larger size variants.

How is volume calculated?

For rectangular areas: Volume = Length × Width × Depth. For circular areas: Volume = π × (Diameter / 2)² × Depth. All dimensions are converted to the same unit before multiplying.

How do I convert cubic yards to tons?

Multiply the volume in cubic yards by the density in tons per cubic yard. For river rock at 1,682 kg/m³, one cubic yard weighs approximately 1.41 short tons. This calculator handles the conversion automatically.

How deep should I lay river rock?

For decorative ground cover and garden beds, 2–3 inches (5–8 cm) is standard. For pathways where foot traffic is expected, use 3–4 inches (8–10 cm). For erosion control and drainage applications, 4–6 inches (10–15 cm) or more may be required.

Why should I add a waste factor?

Some rock is inevitably lost during delivery, spreading, and settling. A 5–10% waste factor ensures you order enough material to complete the project without a costly second delivery.

How many bags of river rock do I need?

Divide the total weight in pounds by the bag weight shown on the product. Common bag sizes are 0.5 cu ft (about 50 lb) and 0.4 cu ft. Alternatively, divide your cubic feet result by the coverage per bag listed on the packaging.

River Rock Calculator

Name: River Rock Calculator
Availability: InStock
Author: Nham Vu

Calculate the volume and weight of river rock needed to cover any rectangular or circular area at a given depth.

Area & Depth

Length (ft)

Width (ft)

Depth (in)

Waste Factor (%)

River Rock Size

Summary