Landscape Rock Calculator
Free landscape rock calculator to estimate cubic yards, tons, and cost for your project. Works with pea gravel, crushed stone, river rock, decomposed granite, and more.
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Rock Type Comparison
Different rocks have different densities, which directly affects how many tons you need. Here's how common landscape rocks compare:
| Rock Type | Density (lb/ft³) | Tons/Yard³ | Best For |
|---|---|---|---|
| Pea Gravel | 100 | 1.35 | Walkways, patios, gardens, drainage |
| Crushed Stone | 110 | 1.49 | Driveways, road base, French drains |
| River Rock | 105 | 1.42 | Dry creek beds, decorative borders |
| Decomposed Granite | 95 | 1.28 | Walkways, rustic patios, xeriscaping |
| Lava Rock | 55 | 0.74 | Garden beds, planters, fire pits |
| Limestone | 100 | 1.35 | Driveways, agricultural use |
How Deep Should I Go?
Depth depends on your project. Too thin and rock shifts or exposes soil. Too deep and you waste money.
| Depth | Best For | Sq Ft per Ton (Pea Gravel) |
|---|---|---|
| 2 inches | Decorative ground cover, mulch replacement | 120 ft² |
| 3 inches | Walkways, garden paths | 80 ft² |
| 4 inches | Driveways, high-traffic areas | 60 ft² |
| 6 inches | Drainage projects, dry creek beds | 40 ft² |
Landscape Rock Tips
Always install landscape fabric before spreading rock. It prevents weeds from growing through and stops rock from sinking into the soil over time. Overlap fabric edges by 6-12 inches for full coverage.
Order 10% extra for simple rectangular beds, 15% for irregular shapes, and 20% for complex features like dry creek beds. It's cheaper to have a little extra than to run short mid-project.
For pathways, use landscape edging to keep rock contained. Edging prevents migration into lawn areas and gives a clean, professional look to your project.
Frequently Asked Questions
At 2 inches deep with pea gravel (100 lb/ft³), you need about 0.83 tons. At 3 inches, you need about 1.25 tons. At 4 inches, about 1.67 tons. Multiply by your rock type's density divided by 100 for other materials.
2 inches for decorative ground cover, 3 inches for walkways and garden paths, 4 inches for driveways and high-traffic areas, and 6+ inches for drainage projects and dry creek beds.
Pea gravel is smooth and rounded (100 lb/ft³), great for paths and decorative use. Crushed stone is angular (110 lb/ft³), compacts better for driveways and base layers. Crushed stone locks together; pea gravel shifts underfoot.
Pea gravel $30-55/ton, crushed stone $30-50/ton, river rock $45-100/ton, decomposed granite $35-60/ton, lava rock $50-80/ton. Prices vary by region and supplier. Delivery typically adds $50-150 per order.
Yes, landscape fabric is strongly recommended. It prevents weeds from growing through, stops rock from sinking into soil, and makes future removal or replacement much easier. Overlap edges by 6-12 inches.
Add 10% for simple rectangular areas, 15% for irregular shapes, and 20% for complex projects like dry creek beds. This accounts for spillage, uneven ground, and settling. Better to have extra than run short.