River Rock Calculator
Enter your area and depth to get the tons, cubic yards, and bags of river rock you need — updates instantly as you type.
Assumes an average river rock density of 1.5 tons per cubic yard. Larger decorative rock (3"+) is often better ordered in bulk by the ton rather than by the bag.
How This Is Calculated
The calculator multiplies your area (length × width) by depth to get cubic feet, converts to cubic yards, then multiplies by river rock's average density of 1.5 tons per cubic yard.
tons = cubic yards × 1.5
bags = cubic feet ÷ bag size
Worked example: a 10 ft × 3 ft border at a 3-inch depth is 30 sq ft × 0.25 ft = 7.5 cubic feet, or about 0.28 cubic yards — roughly 0.42 tons, or 15 of the standard 0.5 cu ft bags. Buy 5–10% extra to cover uneven ground and settling.
River Rock Sizes & Applications
"River rock" covers a range of sizes, and which one you want changes both the look and the coverage math. Unlike crushed stone — which is mechanically broken and angular — true river rock is naturally smoothed and rounded by years of water erosion, giving it a softer look and a mix of earthy tan, gray, and rust tones rather than a single uniform color. That natural sourcing is also part of why it costs more per ton than crushed alternatives. The three most common size grades:
| Size | Best for | Recommended depth |
|---|---|---|
| 1"–2" | Pathways, ground cover, smaller decorative beds — comfortable underfoot | 2–3 in |
| 2"–3" | General landscaping, borders, standard drainage beds — the most common size sold | 3–4 in |
| 3"–5" | Dry creek beds, erosion control, water features, drainage swales | 4–6 in |
Bigger stone needs a deeper layer to look intentional rather than sparse — a 2-inch layer of 3"–5" rock will show bare landscape fabric between stones, while the same depth in 1"–2" rock gives full coverage. The calculator's density (1.5 tons/yd³) holds roughly steady across all three sizes.
Coverage Per Ton
Since suppliers usually sell and deliver by the ton, it helps to know how far a ton actually goes at different depths. One ton of river rock is about 0.67 cubic yards, or 18 cubic feet:
| Depth | Coverage per ton |
|---|---|
| 2 in | ≈108 sq ft |
| 3 in | ≈72 sq ft |
| 4 in | ≈54 sq ft |
| 6 in | ≈36 sq ft |
Depth Guide
Use 2–3 inches for decorative borders and pathway edging, 3–4 inches for general drainage beds and dry creek beds, and 4–6 inches for erosion-control areas or anywhere the rock needs to stand up to moving water. Larger 3"–5" rock should default to the deeper end of these ranges so individual stones sit close enough together to hold their position. See the full gravel depth guide for depth recommendations across every project type.
Because river rock is rounded rather than angular, it doesn't interlock the way crushed stone does, so it can shift or migrate under running water. For drainage swales and anywhere water moves through the bed regularly, lay a geotextile fabric underneath before placing the rock — it stops the stones from sinking into the soil beneath and keeps weeds from pushing through.
Pricing
River rock typically costs more per ton than pea gravel or crushed stone, since larger stones are hand-selected or screened rather than simply crushed. Expect $35–$70 per ton (roughly $45–$90 per cubic yard) for standard 2"–3" river rock, with 1"–2" sizes at the lower end and 3"–5" decorative rock often running $10–$20 more per ton for the larger, more selective grading. Bagged river rock at a hardware store often runs $6–$10 per 0.5 cu ft bag — fine for a small accent bed, but two to three times the per-yard cost of a bulk delivery once a project passes a cubic yard or so. Get an exact total for your project with the gravel cost calculator.
Frequently asked questions
How much river rock do I need?
Multiply the area of your space by your chosen depth to get cubic feet, then divide by 27 for cubic yards. For a typical 3-inch depth, budget about 0.009 cubic yards per square foot, or just use the calculator above.
How many tons of river rock are in a cubic yard?
One cubic yard of river rock weighs approximately 1.5 tons (about 3,000 lbs) — slightly heavier than pea gravel because larger stones pack more densely.
What depth should river rock be?
Use 2–3 inches for decorative borders and 3–4 inches for drainage beds, dry creek beds, or erosion control. See our gravel depth guide for more use cases.
What size river rock is best for a dry creek bed?
Most dry creek beds mix sizes for a natural look — 3"–5" rock for the "creek bed" itself, sometimes with a few larger accent stones, and 1"–2" rock along the banks. Using a single uniform size tends to look less realistic.
Is river rock more expensive than pea gravel?
Usually, yes. River rock costs $35–$70 per ton versus $30–$65 for pea gravel, since larger stones require more selective screening. The gap widens further for 3"–5" decorative sizes.