River rock calculator
River rock (smooth rounded stones ¾–5 inches) is sold by weight and coverage varies by size. Enter the area you're covering for yards, tons and bags.
Result
River rock needed
How much river rock do I need?
Formula
ft³ = area (ft²) × depth (in) ÷ 12 · yd³ = ft³ ÷ 27 · tons ≈ yd³ × 1.25
Example: a 20 ft dry-creek strip 3 ft wide at 3 inches of 1–3 inch rock: 60 ft² × 3/12 = 15 ft³ = 0.56 yd³ ≈ 0.7 tons (28 of the 0.5 ft³ bags).
Coverage per yard by size
| Stone size | Coverage at 2 in | Coverage at 3 in |
|---|---|---|
| ¾–1 in (small) | ~160 ft² | ~108 ft² |
| 1–3 in (standard) | ~150 ft² | ~100 ft² |
| 3–5 in (large) | ~130 ft² | ~90 ft² |
| 5–8 in (boulder mix) | ~110 ft² | ~75 ft² |
Bigger stones have bigger voids, so a yard of them covers slightly less — and reads “rockier”. For dry creek beds meant to move water, put 2–3 in of rock over weed fabric, with boulders set along the edges.
Cost reality
River rock is a decorative product: $100–200+/ton bulk (region and color driven; Mexican beach pebble is 3–5× plain tan). For large areas where looks matter less, crushed stone or mulch does the job at a third of the price.
Frequently asked questions
How much river rock to cover 200 square feet?
At 3 inches: 50 ft³ = 1.85 yd³ ≈ 2.3 tons of 1–3 in rock, or about 100 bags — bulk delivery strongly recommended.
How deep should a dry creek bed be?
4–6 inches of rock in a dug swale 6–10 in deep, lined with fabric. Steeper yards: bigger stone (3–5 in) resists washing.
How many bags of river rock equal a yard?
About 54 of the 0.5 ft³ bags — at $8/bag that's $430+/yard versus ~$130/yard bulk. Bags are for one accent pot.
Does river rock prevent weeds?
Only with landscape fabric underneath. On bare soil, dust settles between stones and weeds follow within a season.
Which is better: river rock or mulch?
Rock costs more up front but never needs replacing and holds heat for succulents/Mediterranean beds; mulch feeds soil and suits mixed borders. Many yards use both.