Coverage
How Much River Rock Do I Need?
River rock is sold by weight, and how much you need depends on your area, the stone size and the depth. Here is the depth to use, coverage per tonne, and a fast lookup table.
How deep should river rock be?
Match the depth to the stone size — you want at least two layers of stone so the ground does not show through:
| Stone size | Recommended depth | Typical use |
|---|---|---|
| Small (3/8–3/4 in) | 2 in (50 mm) | Beds, borders, ground cover |
| Medium (1–2 in) | 3 in (75 mm) | Pathways, drainage areas |
| Large (2–5 in) | 4 in (100 mm)+ | Dry creek beds, accents |
For weed control, lay landscape fabric first, then the river rock on top.
River rock coverage per tonne
River rock is smooth and rounded, with a density around 1.4–1.5 t/m³. One tonne covers roughly:
- ≈ 14 m² (150 ft²) at 5 cm (2 in) deep
- ≈ 9 m² (100 ft²) at 7.5 cm (3 in) deep
- ≈ 7 m² (75 ft²) at 10 cm (4 in) deep
River rock by bed size
For a 2 inch depth of small-to-medium river rock:
| Bed size | Area | River rock |
|---|---|---|
| 10 x 10 ft | 100 ft² | ≈ 0.6 yd³ (≈ 0.9 t) |
| 10 x 20 ft | 200 ft² | ≈ 1.2 yd³ (≈ 1.8 t) |
| 20 x 20 ft | 400 ft² | ≈ 2.5 yd³ (≈ 3.6 t) |
Use the Landscape Rock Calculator for your exact bed, or compare with the Pea Gravel Calculator. See crushed stone vs gravel to choose between angular and rounded stone.
Frequently asked questions
How much river rock do I need per square foot?
At a 2 inch depth, one tonne of river rock covers about 150 ft², so you need roughly 13 lb (about 6 kg) per square foot. For a 100 ft² bed at 2 inches, plan on about 0.9 tonnes.
How deep should river rock be?
About 2 inches for small 3/8–3/4 inch stone, 3 inches for 1–2 inch stone, and 4 inches or more for large 2–5 inch rock. You want at least two layers so the ground underneath does not show.
How much area does a tonne of river rock cover?
Roughly 14 m² (150 ft²) at 2 inches deep, 9 m² (100 ft²) at 3 inches, and 7 m² (75 ft²) at 4 inches. River rock is fairly light, so it covers a bit more per tonne than crushed stone.
Should I put fabric under river rock?
Yes, for landscaping beds lay landscape fabric first. It blocks weeds and stops the rock from sinking into the soil, which keeps the bed looking clean and makes the stone easier to maintain.
Disclaimer: This guide gives general estimates for planning. Actual gravel quantities, weights and prices vary with material type, particle size, moisture, compaction, supplier and your province. Costs are material-only ballparks in Canadian dollars and exclude labour, delivery and taxes unless stated. Always confirm quantities and prices with your local supplier.