How much river rock do you need? Enter the size and depth of your bed, border or dry creek to see how many cubic yards and tons of river rock to order.
How to use the river rock calculator
- Pick a rectangle or a circle and enter the size of the area. Break L-shapes and curves into simpler pieces and add the results.
- Enter the depth you want once the material is spread and levelled. Depth is usually easiest in inches.
- Keep an allowance for settling and low spots unless the ground is already flat and firm.
- Check the weight per cubic yard against your supplier’s figure, then add a price to get a cost estimate.
River rock formulas
Volume (ft³) = length (ft) × width (ft) × depth (ft) Cubic yards = cubic feet ÷ 27 Tons = cubic yards × weight per yd³ (lb) ÷ 2,000 With extra = volume × (1 + extra % ÷ 100)
Suppliers price river rock by the ton or by the cubic yard, so the calculator gives both. Enter the weight per cubic yard your yard quotes if it differs from the default, because that number is what turns yards into tons.
Worked example: 20 × 8 ft at 3 in deep
- Volume: 20 ft × 8 ft × 0.250 ft = 40.0 ft³.
- Add 10% extra: 40.0 × 1.10 = 44.0 ft³.
- Cubic yards: 44.0 ÷ 27 = 1.63 yd³.
- Tons: 1.63 × 2,700 ÷ 2,000 = 2.20 tons.
How deep to go
River rock is usually laid 2–3 in deep in beds and borders, and 3–4 in in a dry creek bed or drainage swale where water moves through it.
Coverage at each depth
| Depth | One cubic yard covers | One ton covers | Per 100 ft² |
|---|---|---|---|
| 2 in | 162 ft² | 120 ft² | 0.62 yd³ |
| 3 in | 108 ft² | 80 ft² | 0.93 yd³ |
| 4 in | 81 ft² | 60 ft² | 1.23 yd³ |
| 6 in | 54 ft² | 40 ft² | 1.85 yd³ |
Figures use 2,700 lb per cubic yard. Change the weight in the calculator and the numbers move with it.
Questions
How much does a yard of river rock weigh?
About 2,500–2,900 lb, or roughly 1.3–1.45 tons, per North Bay Materials’ density chart. Larger stone packs with more air gaps and comes in at the lower end.
How many square feet does a ton of river rock cover?
About 80 ft² at 3 in deep and 60 ft² at 4 in, using 2,700 lb per cubic yard.
How deep should river rock be in a bed?
2–3 in is enough to cover the soil and hold its colour. Dry creek beds and drainage runs are usually 3–4 in so water moves through the stone rather than over it.
Is river rock heavier than pea gravel?
Per cubic yard they are close, 2,500–2,900 lb for both. River rock simply comes in larger pieces, so the same yard covers the same area but needs more depth to look right.
How much river rock for 100 sq ft at 3 in deep?
100 × 0.25 ft = 25 cu ft ÷ 27 = about 0.93 cubic yards.
Sources
- Landscape Materials Density Chart, North Bay Materials.
Used for: Typical weights per cubic yard for gravel, crushed rock, soil and mulch. - NIST Guide to the SI, Appendix B.8: Factors for units listed alphabetically, National Institute of Standards and Technology.
Used for: Exact inch and foot definitions; cubic foot and cubic yard conversions.