How to Calculate Stone for Landscaping
The formula for calculating stone volume is straightforward: multiply the length by the width to get the area in square feet, then multiply by the depth converted to feet. Divide by 27 to convert cubic feet to cubic yards (since there are 27 cubic feet in one cubic yard).
Cubic Yards = (Length × Width × Depth_in_feet) / 27
Depth_in_feet = Depth_in_inches / 12
Example: 20 ft × 10 ft × 3 inches deep
= (20 × 10 × 0.25) / 27
= 50 / 27
≈ 1.85 cubic yards
Tons = Cubic Yards × density factor
Crushed Stone: ~1.4 tons/yd³
Pea Gravel: ~1.3 tons/yd³
River Rock: ~1.35 tons/yd³
Stone Type Comparison
| Stone Type | Density (tons/yd³) | Best Uses | Typical Cost/ton |
|---|---|---|---|
| Crushed Stone | 1.4 | Driveways, base material, drainage | $30–$55 |
| Pea Gravel | 1.3 | Pathways, play areas, drainage | $35–$65 |
| River Rock | 1.35 | Decorative beds, water features | $50–$90 |
| Lava Rock | 0.9 | Decorative, mulch replacement | $75–$120 |
| Marble Chips | 1.45 | Decorative, formal gardens | $100–$180 |
Recommended Coverage Depths
| Application | Recommended Depth |
|---|---|
| Pathway / walkway | 2–3 inches |
| Decorative garden bed | 2–3 inches |
| Driveway (base) | 4–6 inches |
| Drainage / French drain | 6–12 inches |
| Erosion control | 3–5 inches |