How deep to go
| Use | Published figure | Source |
|---|---|---|
| River rock decorative beds | 2 to 4 in | earthstonerock.com |
| Crushed rock ground cover | 2 to 3 in | earthstonerock.com |
| Inorganic mulch, Utah State | 2 to 3 in | extension.usu.edu |
Earthstone lists 2 to 4 inches for river rock beds and 2 to 3 inches for crushed rock ground cover. Utah State Extension gives 2 to 3 inches for inorganic mulch such as gravel. Bigger stone needs the deeper end so the soil does not show between the rocks.
Working it out
Cubic yards = area (sq ft) × depth (in) ÷ 12 ÷ 27. Tons = cubic yards × weight per cubic yard.
Example: 20 × 6 ft at 3 inches is 1.11 cubic yards of river rock, about 1.56 tons at 1.40 tons per cubic yard.
Rochester Concrete Products' install guide adds 10% for compaction and uneven ground.
Common questions
How much gravel do I need for a landscape rock bed?
Measure the area, choose a depth from the table above and enter both in the calculator. It gives cubic yards, tons and bags.
Should I order extra?
Rochester Concrete Products' install guide adds 10% for compaction and uneven ground. Loose stone also compacts, so a compacted layer needs more loose material than its finished depth suggests.
Related calculators
Sources
- https://www.earthstonerock.com/pages/frequently-asked-questions
- https://extension.usu.edu/cwel/research/water-wise-landscaping-mulch.php
- https://hellogravel.com/guides/2025-gravel-prices-per-ton-delivered-cost-calculator-and-regional-rates/
- https://homeguide.com/costs/gravel-prices