River rock calculator
Calculate this loadMeasure the bed, pick a depth at least as large as the stone, and convert to yards and tons at 1.25 tons/yd³.
Project calculator
Area 1
Cubic yards
0.93 yd³
Tons
1.16 t
2 cu ft bags
13
Estimated cost
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River rock planning density 1.25 t/yd³ (Supplier bulk tables for 1–3 inch washed river rock). Order 1 yd³ with 5% waste. 3 cu ft bags: 9.
River rock is washed, rounded, and sold in size bands: 3/4 inch, 1–3 inch, 3–5 inch, and cobble. Coverage math stays the same; appearance does not. You cannot hide soil with stone smaller than the gaps, and you cannot build a 2-inch layer out of 4-inch cobble. Set depth to at least the nominal stone size.
Rounded rock rolls. On a slope it wants fabric, edging, and sometimes a hidden angular base. In a dry creek it should sit in a shallow trench, not on the lawn. The 1.25 tons/yd³ density reflects typical washed 1–3 inch product with more voids than crushed stone.
Color depends on the quarry. Photograph a damp pile; dry rock is paler than the website. Order a sample bag if the house colors are non-negotiable.
Related calculators cover landscape rock (mixed decorative) and pea gravel (the small, path-friendly cousin).
Formula
Yards = L × W × D ÷ 27. Tons ≈ yards × 1.25 for 1–3 inch washed river rock.
Worked example
A 24 × 6 ft dry creek at 3 inches is 144 × 0.25 ÷ 27 = 1.33 yd³, about 1.67 tons.
River rock on the ground
Typical cover is 3 inches. Range 1.15–1.45 t/yd³. Larger cobble packs with more voids, so a yard covers less area.
Density table
| Material | t / yd³ | lb / yd³ | Source |
|---|---|---|---|
| River rock | 1.25 | 2500 | Supplier bulk tables for 1–3 inch washed river rock |
| Landscape rock | 1.3 | 2600 | Decorative rock planning weight, mid-range of washed stone |
| Rock | 1.35 | 2700 | Generic decorative/riprap planning density |
Related calculators
Landscape rock calculator
Use this for mixed decorative stone when the yard has not given you a tighter product name or density.
Pea gravel calculator
Rounded 1/4–3/8 inch pea gravel is a 2-inch path material. It migrates, so plan edging and a little extra.
Rock calculator
Large stone has more voids than gravel. Use this when the yard calls it rock, riprap, or ‘landscape stone’ without a tighter name.