Mulch & Landscaping
Landscape Rock & Gravel Calculator: How Much Do I Need?
Use this landscape rock calculator to estimate decorative stone, gravel, or rock volume for garden beds, paths, borders, and small outdoor projects.
Estimated rock volume
Landscape rock result
20.00 cu ft
120 sq ft at 2 inches deep equals 20.00 cubic feet or 0.74 cubic yards.
Recommended rock depth
| Project | Typical depth | Planning note |
|---|---|---|
| Decorative garden bed | 2 to 3 in | Enough for coverage without excessive weight. |
| Walkway or path | 3 to 4 in | Use a stable base and compact as needed. |
| Tree ring | 2 in | Keep rock and fabric away from the trunk flare. |
| Refresh layer | 1 in | Use when existing rock is still mostly in place. |
Volume examples
| Area | Depth | Cubic feet | Cubic yards |
|---|---|---|---|
| 120 sq ft | 2 in | 20.00 cu ft | 0.74 cu yd |
| 200 sq ft | 2 in | 33.33 cu ft | 1.23 cu yd |
| 300 sq ft | 3 in | 75.00 cu ft | 2.78 cu yd |
| 500 sq ft | 4 in | 166.67 cu ft | 6.17 cu yd |
About tons and weight
Rock is often sold by the ton, but this calculator estimates volume. Weight depends on rock type, size, moisture, and supplier. After you calculate cubic yards, ask the supplier how many tons per cubic yard apply to that material.
Common mistakes
- Using bag weight as if it were volume.
- Forgetting to account for edging curves or irregular shapes.
- Ordering no extra rock for low spots or settling.
- Using too shallow a layer for paths that need stability.
FAQ
Landscape rock calculator FAQ
How do I calculate landscape rock?
Multiply square feet by depth in inches, then divide by 12 for cubic feet. Divide by 27 for cubic yards.
How deep should landscape rock be?
Two to three inches is common for decorative beds. Paths may need three to four inches depending on base and rock size.
Should I order extra rock?
Yes. A 5% to 10% extra allowance is useful for uneven areas, edging, and settling.
How do I convert cubic yards to tons?
Ask the supplier for the material's tons per cubic yard. The conversion changes by rock type and moisture.
Can I use the mulch calculator for rock?
The volume math is similar, but rock weight and installation details are different. This page is focused on rock and gravel planning.