How the landscape rock calculator works
Cubic yards = Area × Depth (in) ÷ 12 ÷ 27 × (1 + extra)
Tons = Cubic yards × rock weight (tons per yd³)
How deep should landscape rock be?
- Small rock (3/8–3/4 in): 2 inches covers well.
- River rock 1–3 in: 2–3 inches, about two stones deep.
- Larger cobbles (3–5 in): 3–4 inches, enough to hide the fabric.
Why rock type changes the order
Dense stone like river rock weighs roughly 1.3 tons per cubic yard, while lava rock is so porous that a yard weighs only about half a ton. Suppliers sell by the ton, so the same bed can need very different tonnage.
Install tips
- Lay landscape fabric first to keep weeds and soil from working up through the rock.
- Edge the bed with steel, stone or plastic edging so rock stays out of the lawn.
- Rock holds heat; keep it a few inches from plant stems in hot climates.
Frequently asked questions
How much area does a ton of river rock cover?
At 2 inches deep, roughly 125 square feet; at 3 inches, about 83 square feet.
How much does a yard of river rock weigh?
Roughly 1.3 tons (2,600 lb), depending on size and moisture.
Is landscape rock cheaper than mulch?
Rock usually costs more up front but does not need replacing every year the way mulch does.