River Rock Calculator
Enter your bed or creek-bed area and how deep you want the rock layer. You'll get the amount in cubic yards, tons and bags — plus cost if you know your supplier's price.
Results
How the river rock calculator works
Like all loose stone, river rock is quoted by the cubic yard or the ton. The calculator multiplies your area by the depth of the layer to get volume, then converts to weight using river rock's density — about 94 lb per cubic foot, or 1.27 tons per cubic yard.
Formula: Length (ft) × Width (ft) × Depth (ft) ÷ 27 = cubic yards, then × 1.27 = tons
| Rock size | Recommended depth | Coverage per ton |
|---|---|---|
| ⅜"–1" (pebbles) | 2" | ≈ 125 sq ft |
| 1"–3" (standard) | 3" | ≈ 85 sq ft |
| 3"–8" (large) | 4"+ or single layer | ≈ 60 sq ft |
Rule of thumb: the layer should be about twice as deep as the largest stone size, so the ground never shows through. Very large stones (4"+) are often set as a single hand-placed layer instead.
River rock tips
- For dry creek beds, dig a shallow swale, line it with fabric, and use two sizes: large stones along the edges, smaller rock in the channel — it looks natural and stays put in rain.
- Always put woven landscape fabric underneath; river rock sinks into bare soil within a couple of seasons.
- Round rock rolls underfoot — don't use it for walkways. Use crushed gravel for paths and save river rock for beds and borders.
- Buying by the ton is usually cheaper than bags once you need more than about 20 bags (½ cubic yard).
Frequently asked questions
How much does a ton of river rock cover?
At a 3-inch depth, one ton of standard 1"–3" river rock covers about 85 square feet. Smaller pebbles laid 2 inches deep stretch to roughly 125 sq ft per ton.
How many tons of river rock are in a cubic yard?
About 1.27 tons. River rock is slightly lighter than crushed stone because the rounded stones don't pack as tightly.
What do I put under river rock?
A woven landscape fabric (not plastic sheeting). It stops the rock from sinking into the soil, keeps weeds manageable, and lets water drain through.
Is river rock cheaper than mulch?
Per application it costs more — $60–140 per ton versus $30–60 per yard of mulch. But rock doesn't decompose, so over 5–10 years it's usually cheaper than re-mulching every year or two.