Landscape Stone Calculator
Works for crushed stone, river rock, lava rock, marble chips and other decorative stone. Enter your area and depth to get yards, tons and bags.
Results
How the stone calculator works
The math is simple: multiply the length and width of the area to get square footage, then multiply by the depth of the layer to get volume. Suppliers sell by the cubic yard (27 cubic feet), so the calculator divides by 27, and uses the material's density to convert volume into weight.
Formula: Length (ft) × Width (ft) × Depth (ft) ÷ 27 = cubic yards, then cubic feet × density (lb/ft³) ÷ 2,000 = US tons.
| Stone type | lb/ft³ | tons/yd³ |
|---|---|---|
| Crushed stone ¾"–1" | 100 | ≈ 1.35 |
| River rock | 94 | ≈ 1.27 |
| Lava rock | 45 | ≈ 0.61 |
| Marble chips | 96 | ≈ 1.30 |
Note how light lava rock is — you get more than twice the coverage per ton compared to river rock, which is why it's often the budget option for large decorative areas despite a higher price per bag.
Tips before you order
- Decorative ground cover only needs 2" of stone; use 3–4" for larger stones (1.5"+) so the ground doesn't show through.
- Always lay landscape fabric under decorative stone — pulling weeds out of rock is miserable.
- River rock rolls underfoot; use crushed (angular) stone for paths, as it locks together.
- Stone doesn't decompose like mulch, but it does sink into soil over the years — edging keeps it contained.
Frequently asked questions
How many tons of stone are in a cubic yard?
Most landscape stone runs 1.2–1.4 tons per cubic yard. Lava rock is the exception at only about 0.5–0.65 tons per cubic yard.
How much does a ton of river rock cover?
At 2 inches deep, a ton of river rock covers roughly 120–130 square feet. Larger stones laid thicker (3–4") cover 60–80 sq ft per ton.
What size of rock is best for landscaping?
For ground cover, ¾"–1½" stone is the most versatile. Pea-sized stone migrates and larger cobbles are hard to walk on; save 2"+ river rock for accents and dry creek beds.
Do I need fabric under landscape rock?
Yes — a woven landscape fabric stops the stone from sinking into the soil and makes any weeds pull easily. Skip plastic sheeting, which traps water.