River rock is heavy and round
Washed river rock runs about 1.6 tons per cubic yard — heavier than crushed stone per yard and impossible to compact (round stones roll), which is why it's a decorative top dressing over fabric, not a base. Depth for landscaping coverage: 2–3 inches over weed fabric.
Buy by the ton, spread by the yard
Landscape yards sell river rock by the ton or by the bucket; the calculator's tonnage is the number to order. Budget delivery on top — rock is heavy enough that the delivery fee is real money, and wheelbarrowing two tons from the driveway is a genuine day of work.
Sources and standards
Where these figures come from
Every formula on this page is implemented from the published reference material below. Where a value depends on a regional code, the calculator lets you override it rather than assuming one jurisdiction.
- USDA Natural Resources Conservation Service — soil texture, bulk density and seeding rate guidance.
- US Geological Survey — mineral commodity data and aggregate density references.
- National Stone, Sand & Gravel Association — aggregate grading and product specification references.
Figures, formulas and reference tables last verified: 19 September 2026.