The Formula
One formula works for all landscape rock, river rock, and decorative stone:
Square Feet × Depth (inches) ÷ 324 = Cubic Yards of Rock
- Example: 300 sq ft flower bed at 3 inches: 300 × 3 ÷ 324 = 2.78 yd³
- Round up to the nearest 0.25 yd³ when ordering bulk
- Add 10–15% for waste and variation in rock size
Calculate Your Rock Order Now
Enter bed dimensions and depth — get cubic yards and weight instantly.
Open Landscape Rock Calculator →How Deep Should Landscape Rock Be?
| Rock Size / Type | Recommended Depth | Why |
|---|---|---|
| Pea gravel (3/8") | 2 – 3 inches | Small rock fills gaps quickly |
| Decomposed granite | 2 – 3 inches | Compacts into stable surface |
| River rock (1–2") | 2 – 3 inches | Single layer is enough |
| River rock (2–4") | 3 – 4 inches | Larger stones need more depth |
| Lava rock | 2 – 3 inches | Very light — more depth = less weight |
| Mexican beach pebble | 3 – 4 inches | Dense; looks best fully layered |
| Rip rap / large boulders | Single layer | Calculate by count, not depth |
Key Takeaway
Most landscape rock projects use 2–3 inches of depth. Going deeper doesn't improve weed suppression much but significantly increases cost. Use landscape fabric underneath for weed control instead.
Coverage Table: Cubic Yards → Square Feet
| Cubic Yards | At 2" Deep | At 3" Deep | At 4" Deep |
|---|---|---|---|
| 0.5 yd³ | 81 sq ft | 54 sq ft | 40 sq ft |
| 1 yd³ | 162 sq ft | 108 sq ft | 81 sq ft |
| 2 yd³ | 324 sq ft | 216 sq ft | 162 sq ft |
| 3 yd³ | 486 sq ft | 324 sq ft | 243 sq ft |
| 5 yd³ | 810 sq ft | 540 sq ft | 405 sq ft |
| 10 yd³ | 1,620 sq ft | 1,080 sq ft | 810 sq ft |
Landscape Rock Types Compared
| Rock Type | Weight / Yd³ | Cost / Yd³ | Best For |
|---|---|---|---|
| Pea gravel | 2,800 lbs | $30 – $55 | Pathways, driveways, drainage |
| River rock (1–2") | 2,800 – 3,000 lbs | $45 – $75 | Beds, borders, water features |
| River rock (3–5") | 2,900 – 3,200 lbs | $55 – $90 | Borders, erosion control |
| Decomposed granite | 2,500 – 2,700 lbs | $30 – $50 | Patios, pathways, xeriscape |
| Lava rock | 1,300 – 1,600 lbs | $80 – $120 | Mulch replacement, beds |
| White marble chips | 2,400 – 2,700 lbs | $100 – $175 | Premium decorative beds |
| Mexican beach pebble | 3,000 – 3,200 lbs | $150 – $250 | High-end decorative, pools |
Bags vs. Bulk Rock
- 0.5 yd³ or less → Bags from home improvement stores (0.5 cu ft bags)
- 0.5 yd³ and above → Bulk from landscaping suppliers — 50–70% cheaper
- 1 cubic yard ≈ 54 bags of 0.5 cu ft rock = expensive. Bulk delivery of 1 yard costs $40–$80 delivered
💡 Don't forget landscape fabric
Always lay landscape fabric under rock. It prevents weeds from growing up through the stone and prevents the rock from sinking into the soil over time. Add a fabric cost of $0.10–$0.25/sq ft to your project budget.
Frequently Asked Questions
How many square feet does a ton of landscape rock cover?
- At 2 inches deep: 1 ton covers ≈ 100–120 sq ft
- At 3 inches deep: 1 ton covers ≈ 65–80 sq ft
- Exact coverage varies by rock density and size
How many cubic yards is a ton of landscape rock?
Most landscape rock weighs 2,700–3,000 lbs per cubic yard. At 2,800 lbs/yd³: 1 ton = 0.71 cubic yards.