River Rock Calculator
To cover a 10 × 10 ft flower bed at the standard 2-inch decorative depth you need about 0.62 cubic yards of river rock plus 10% waste — roughly 37 bags of 0.5 cu ft river rock.
Reviewed by The ponderloop teamUpdated 2026-07-15How we calculate
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0 cu yd + 0% waste = 0 cu yd
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How this number is calculated
0 cu yd (no waste added) ÷ 0.0185 cu yd per bag = 0 bags
Shopping list
- River rock (0.5 cu ft bag)
- Landscape fabric
- Landscape fabric staples
- Steel landscape edging
- Garden rake
- Heavy-duty work gloves
0.0 cu yd — ~0% of a standard truck load
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Methodology & assumptions
Volume is calculated as bed length × width × (depth in inches ÷ 12), then divided by 27 to convert cubic feet to cubic yards. A waste percentage is added for irregular bed edges and settling, and the result is divided by the coverage per bag (0.0185 cu yd for a 0.5 cu ft bag) and rounded up to the next whole bag.
- University extension landscaping guides (river rock depth and fabric recommendations)
- Manufacturer bag-yield specs (0.5 cu ft river rock bag)
- Typical US retail price range for decorative river rock, 2026
Worked examples
| Room | Result |
|---|---|
| 10 × 10 ft flower bed, 2 in depth, standard waste | 0.62 cu yd + 10% waste ≈ 0.68 cu yd → 37 bags |
| 20 × 3 ft dry creek bed, 2 in depth, standard waste | 0.37 cu yd + 10% waste ≈ 0.41 cu yd → 23 bags |
| 15 × 5 ft foundation drainage border, 3 in depth, minimal waste | 0.69 cu yd + 5% waste ≈ 0.73 cu yd → 40 bags |
Frequently asked questions
- How much river rock do I need?
- Multiply the bed length by width in feet, multiply by the depth in feet (inches divided by 12), then divide by 27 to convert cubic feet to cubic yards. Add 10% for waste, then divide by the coverage per bag (0.0185 cu yd for a 0.5 cu ft bag) and round up.
- What's the difference between river rock, gravel, and pea gravel?
- River rock is a decorative product made of larger, rounded washed stones (typically 1-3 in.), sold for flower beds, dry creek beds, and accent borders. Gravel is a functional, crushed or naturally rounded aggregate (usually under 1 in.) used as a structural base under patios, driveways, and paths. Pea gravel is a small, rounded stone (about 3/8 in.) used for walkways and ground cover. All three are landscaping stone, but river rock is priced and sized for looks, while gravel and pea gravel are sized for compaction and drainage.
- Do I need landscape fabric under river rock?
- Yes, in almost every case. Landscape fabric laid before the river rock blocks weeds from growing up through the stone and keeps the rock from sinking into the soil over time, which keeps the bed looking clean and makes future weeding much easier.
- How deep should river rock be for a decorative bed vs. a drainage area?
- A decorative flower bed or accent border typically only needs 2 in. of river rock — enough to fully hide the fabric and soil beneath without wasting material. A dry creek bed or drainage border, where the rock also has to move water, is usually laid 3-4 in. deep for better coverage and to resist scouring during heavy rain.
- Will river rock wash away on a slope?
- Smaller or lighter river rock can migrate downhill on a steep slope during heavy rain, especially without edging to contain it. For slopes, use larger stones (2-3 in. and up), install sturdy edging at the base and sides of the bed, and keep landscape fabric underneath so the rock is not undermined by soil erosion.