River Rock Calculator
Estimate river rock in tons and cubic yards for landscaping, ground cover, and drainage features.
Your River Rock Estimate
- Enter area - length and width of the space to cover.
- Set depth - 2–3" for ground cover, 4–6" for creek beds and drainage.
- Adjust density - 105 lb/ft³ is the average for delivered river rock. Larger stones leave more air gaps and weigh less per ft³.
- Add waste - 10% standard. River rock doesn't compact much - less waste than gravel.
- Plan for delivery - river rock is heavy. Confirm the truck can access your site.
One ton of river rock covers about 75 square feet at 3 inches deep. A 100 square foot dry creek bed at that depth takes just under a cubic yard - about 1.3 tons of rock, or 1.4 once you add the standard 10 percent the calculator applies. Larger stones weigh a little less per yard because of the air gaps between them, which the density field adjusts for. Enter your area and depth above.
How River Rock Sits in a Bed
Planning a River Rock Project
River rock is naturally rounded stone tumbled smooth by water, ranging from 1 inch to 6+ inches in diameter. Its organic look makes it ideal for dry creek beds, water features, border accents, and ground cover around plantings. Unlike mulch, river rock doesn't decompose, blow away, or need annual replacement.
The main cost consideration is that river rock is significantly more expensive per cubic yard than crushed gravel - typically $40 to $100+ per ton depending on size and color (compared to $20–$40 for basic gravel). But since it's a permanent installation, the long-term cost is competitive with materials that need regular replacement.
River Rock Sizes and Applications
River rock comes in graduated sizes. Choosing the right diameter matters for both appearance and function:
| Size | Diameter | Weight | Best For |
|---|---|---|---|
| Small | 1–2 in | ~110 lb/ft³ | Ground cover, between pavers, garden beds |
| Medium | 2–4 in | ~105 lb/ft³ | Dry creek beds, borders, water features |
| Large | 4–8 in | ~100 lb/ft³ | Accent boulders, erosion control, retaining edges |
| Cobble | 6–12 in | ~95 lb/ft³ | Decorative borders, stream channels, focal features |
Larger stones leave more air gaps between them, so they weigh less per cubic foot. This also means you may see landscape fabric through the gaps - plan depth accordingly.
Formulas
Volume-to-weight:
Cubic yards = Volume ÷ 27
Weight (tons) = Volume × Density ÷ 2,000
With waste = Results × (1 + Waste %)
Density decreases as rock size increases due to air gaps. Adjust density down for large cobble (95–100 lb/ft³).
River rock cost by size (2026 US delivered)
| Rock size | Per ton bulk | Per cubic yard | Best application |
|---|---|---|---|
| Small (1-2 in) | $45-$90 | $65-$130 | Drainage, planting beds, paths |
| Medium (2-5 in) | $50-$100 | $70-$145 | Decorative beds, dry creek features |
| Large (4-8 in) | $55-$110 | $80-$160 | Accent features, erosion control |
| Polished river rock | $80-$180 | $115-$260 | Indoor and outdoor decorative |
| Mixed natural river run | $40-$80 | $58-$116 | General landscaping and fill |
River rock costs more than crushed gravel due to natural rounding and washing. Delivery adds $50-$200 per load. Northeast and West Coast average 15-25% above national prices. One ton covers approximately 70-100 sq ft at 2 in depth depending on rock size.
Next Steps
Rock estimated, round out the landscape:
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