Landscape Rock Calculator
Multiply length × width × depth in feet and divide by 27 for cubic yards. A 10 × 10 ft bed covered 3 inches deep takes 0.93 cubic yards of river rock, about 1.15 tons or 50 bags.
Updated October 15, 2026 · How we calculate
Worked example
A 10 × 10 ft bed, 3 inches of river rock:
- Area: 10 × 10 = 100 square feet
- Depth in feet: 3 ÷ 12 = 0.25 ft
- Volume: 100 × 0.25 = 25 cubic feet
- Cubic yards: 25 ÷ 27 = 0.926 cu yd
- Weight: 0.926 × 2,484 lb ÷ 2,000 = 1.15 tons
- Bags: 25 ÷ 0.5 = 50 0.5 cu ft bags
Source: Pavestone river pebbles bag label (0.5 cu ft, 46 lb)
How to choose and how deep
Which rock
- River rock. Smooth, rounded stone for beds, borders and dry creek beds.
- Pea gravel. Small rounded stones for paths, play areas and between pavers.
- Crushed granite. Angular stone that packs down firmly; used for paths and xeriscape beds.
- Lava rock. Light, porous volcanic rock. Less than half the weight of river rock for the same space.
Weight matters for delivery
Rock is heavy. A cubic yard of river rock weighs about 1.24tons, so check your vehicle's payload before hauling it yourself. Lava rock is the exception at about 0.51 tons a yard.
Source: Pavestone river pebbles bag label (0.5 cu ft, 46 lb); Pavestone red volcanic rock bag label (0.5 cu ft, 19 lb)
Bags or bulk
Bagged rock comes in 0.5 cubic foot bags, 54 to a cubic yard. For a small bed, bags are easier; past a yard or so, a bulk delivery usually means far fewer trips.
Quick reference
| Rock | Lb per cubic yard | Tons per cubic yard | Source |
|---|---|---|---|
| River rock | 2,484 | 1.24 | Pavestone river pebbles bag label (0.5 cu ft, 46 lb) |
| Pea gravel | 2,592 | 1.3 | Vigoro pea gravel bag label (0.5 cu ft, 48 lb) |
| Crushed granite | 2,410 to 2,600 | 1.21 to 1.3 | Caltrans Maintenance Manual, Appendix (2014); Missouri DOT, Highway Maintenance Tables and Conversion Factors |
| Lava rock | 1,026 | 0.51 | Pavestone red volcanic rock bag label (0.5 cu ft, 19 lb) |
| Depth | One cubic yard covers |
|---|---|
| 2 in | 162 sq ft |
| 3 in | 108 sq ft |
| 4 in | 81 sq ft |
Questions people ask
How much does a cubic yard of river rock weigh?
About 2,484 pounds, or 1.24 tons, worked out from the weight printed on a bag of river pebbles.
Source: Pavestone river pebbles bag label (0.5 cu ft, 46 lb)
How many bags of rock make a cubic yard?
A cubic yard is 27 cubic feet, so it takes 54 bags of 0.5 cubic feet.
How much area does a cubic yard of rock cover?
162 square feet at 2 inches deep, 108 at 3 inches and 81 at 4 inches.
Is lava rock lighter than river rock?
Yes. A bag of lava rock weighs 1,026 lb per cubic yard against 2,484 lb for river rock, so the same space takes less than half the weight.
Source: Pavestone red volcanic rock bag label (0.5 cu ft, 19 lb); Pavestone river pebbles bag label (0.5 cu ft, 46 lb)