Landscape Rock Calculator
Calculate how many tons, cubic yards, or cubic meters of landscape rock, gravel, or river stone you need for any project.
Landscape rock, gravel, and decorative stone are sold by weight (tons) or by volume (cubic yards or cubic meters). Knowing how much you need before ordering prevents both wasteful over-ordering and the frustration of running short.
The volume formula: Volume = Area × Depth
Where depth is the depth of coverage you want.
Recommended coverage depths:
- Decorative rock / river stone: 50–75mm (2–3 inches)
- Pea gravel (pathways): 50mm (2 inches)
- Crushed stone (driveways): 100–150mm (4–6 inches)
- Drainage gravel (around pipes): 150–300mm (6–12 inches)
- Ground cover / mulch rock: 75mm (3 inches)
Converting volume to weight: Rock and gravel density varies significantly:
| Material | Density (metric) | Density (imperial) |
|---|---|---|
| Pea gravel | 1.6 t/m³ | 1.35 tons/yd³ |
| River rock (1–3") | 1.5 t/m³ | 1.25 tons/yd³ |
| Crushed limestone | 1.7 t/m³ | 1.45 tons/yd³ |
| Decomposed granite | 1.75 t/m³ | 1.5 tons/yd³ |
| Lava rock | 0.9 t/m³ | 0.75 tons/yd³ |
| Marble chips | 1.5 t/m³ | 1.25 tons/yd³ |
Calculating for irregular areas: Break irregular shapes into rectangles and calculate each section separately. Alternatively, estimate the overall bounding rectangle and multiply by 0.75–0.85 to account for irregular edges.
Order tip: Always add 10–15% to account for compaction (especially with finer materials like pea gravel that settle), irregularities in the base, and waste at edges. It’s better to have a small amount left over than to need a second delivery.
Delivery notes: Most landscape suppliers deliver in 1-ton or 1-cubic-yard minimum increments. Round up to the nearest full ton to plan your order accurately.