Find out exactly how much river rock your landscaping, ground cover, or drainage project needs — in tons, cubic yards, bags, and estimated cost.
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Depth:
2″ for ground cover, 3–4″ for full coverage or drainage.
Sets the density used to convert volume → tons.
River rock doesn’t compact, so a small waste margin is enough.
River rock often runs ~$45–130 / ton depending on size and color.
You will need
Estimated river rock cost:
Bags assume 0.5 cu ft each (≈50 lb bag). Tons are US (short) tons. River rock weight varies with size and moisture — always round up and confirm with your supplier.
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How much river rock do I need?
River rock is sold by the ton or cubic yard. Work out the volume, then convert:
Cubic yards = length (ft) × width (ft) × depth (ft) ÷ 27. Multiply cubic yards by the density to get tons. Most river rock weighs roughly 1.35 tons per cubic yard.
As a rule of thumb, one ton of river rock covers about 70 square feet at 3 inches deep, or roughly 100 sq ft at 2 inches for ground cover.
How deep should river rock be?
Use
Depth
Decorative ground cover (over fabric)
2 inches
Full coverage / no soil showing
3 inches
Drainage beds & dry creek beds
3–4 inches
Around larger accent boulders
fill to blend
Lay landscape fabric underneath to stop rock sinking into the soil and to suppress weeds.
River rock densities used
Size
Density (tons / cu yd)
Small river pebble (¾–1″)
1.35
River rock (1–3″)
1.35
Large river rock (3–5″)
1.40
Densities are typical averages; actual weight varies with size, moisture, and source. Use them as a close estimate.
River rock FAQs
How much river rock do I need for landscaping?
Multiply length × width × depth (all in feet) to get cubic feet, divide by 27 for cubic yards, then multiply by about 1.35 for tons. For example, a 20 × 10 ft bed at 3 inches deep needs about 1.85 cubic yards, or roughly 2.5 tons of river rock.
How many tons are in a cubic yard of river rock?
About 1.35 US tons per cubic yard for most river rock. Larger 3–5 inch rock is a little heavier at around 1.4 tons per cubic yard.
How much area does a ton of river rock cover?
About 70 square feet at 3 inches deep, or roughly 100 square feet at 2 inches for decorative ground cover. One cubic yard (≈1.35 tons) covers about 160 sq ft at 2 inches.
How do I calculate river rock for a round area or dry creek bed?
For a circle, area = 3.1416 × radius² (in feet); for a rough creek bed, multiply average length × average width. Then multiply by depth in feet and divide by 27 for cubic yards. Enter that area as the length × width above for a quick estimate.
Should I put fabric under river rock?
Yes — landscape fabric stops the rock from working down into the soil and helps block weeds. It doesn’t change how much rock you need, but it makes the installation last much longer.
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