Landscape Rock Calculator
Calculate how much decorative river rock, lava rock, or landscape stone you need by area and depth.
Results
- Volume needed
- 0.99 cu yd
- With 10% waste
- 1.09 cu yd
- Cubic feet
- 26.67 cu ft
- Cubic meters
- 0.76 m³
- Estimated weight
- 1.41 tons
Estimates only. Round up and buy a little extra to account for waste, spills, and breakage.
Decorative rock is priced by the ton at most yards but ordered by volume, so this calculator reports cubic yards, tons and bag counts side by side.
Rock sizes change the coverage: 3/4 inch stone spreads farther per ton than 2 to 4 inch cobble, which leaves large voids.
Also works as a decorative rock calculator, rock mulch calculator, and lava rock coverage estimator.
How to use the landscape rock calculator
- Enter the shape.
- Enter the length in ft.
- Enter the width in ft.
- Enter the depth in in.
- Enter the waste factor in %.
- Optionally add a price to estimate the total project cost.
- Read your quantities instantly — no sign-up, and you can print the estimate to take to the supplier.
Worked example
Inputs
- Shape
- Rectangle / Square
- Length
- 20 ft
- Width
- 8 ft
- Depth
- 2 in
- Waste factor
- 10 %
Results
- Volume needed
- 0.99 cu yd
- With 10% waste
- 1.09 cu yd
- Cubic feet
- 26.67 cu ft
- Cubic meters
- 0.76 m³
- Estimated weight
- 1.41 tons
Using the example values above, the landscape rock calculator returns 0.99 cu yd (volume needed). Change any field to match your own project and the numbers update instantly.
How much landscape rock per square foot?
At 2 inches deep, one ton of 3/4 inch rock covers roughly 110 to 120 square feet. Larger 1 to 2 inch rock covers about 90 to 100 square feet per ton at the same depth.
For rock beds, 2 inches is enough to hide fabric with small stone and 3 to 4 inches is needed with larger cobble.
Rock versus mulch
Rock costs more up front but does not decompose, so there is no annual top up. Mulch is cheaper per yard and feeds the soil but needs replacing every year or two.
Rock radiates heat, so avoid it around shallow rooted shrubs and on the south side of a house where reflected heat stresses plantings.
How much extra should I order?
Always order a little extra. A 5% waste factor suits simple, square projects; 10% is right for most jobs; bump it to 15–20% for irregular shapes, diagonal patterns, or uneven ground. Running short almost always costs more than the leftover material.
Cubic yard coverage by depth
| Depth | Coverage per cu yd |
|---|---|
| 1 in | 324 sq ft |
| 2 in | 162 sq ft |
| 3 in | 108 sq ft |
| 4 in | 81 sq ft |
| 6 in | 54 sq ft |
Formula
Volume (cu ft) = area × depth ÷ 12. Cubic yards = cu ft ÷ 27. Waste-adjusted = volume × (1 + waste%).
Frequently asked questions
- How deep should landscape rock be?
- Use 2–3 inches over fabric for full ground coverage.
- Should I use fabric under rock?
- Yes, landscape fabric suppresses weeds and keeps rock from sinking into soil.
- How much does a yard of landscape rock weigh?
- About 1.25 to 1.5 tons depending on stone size and moisture. Lava rock is far lighter at roughly 0.5 tons per yard.
- Do I need fabric under landscape rock?
- Yes. Woven landscape fabric keeps stone from sinking into soil and slows weeds. Skip plastic sheeting, which traps water.
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