Most popular landscape rock
10% typical for irregular areas
Area 1
Area: 100.0 sq ft
Estimated Material Cost
$136 - $373
1.4 tons of river rock
Material Quantities
Cost Breakdown
Price per Ton by Rock Type
| Rock Type | $/Ton | lbs/CY |
|---|---|---|
| River Rock (1-3") | $50-$100 | 2,800 |
| Lava Rock | $75-$150 | 1,500 |
| Mexican Beach Pebbles | $200-$500 | 3,000 |
| Decomposed Granite (DG) | $25-$50 | 2,800 |
| Bull Rock / Cobble (3-6") | $45-$90 | 2,600 |
| Crushed Rock / Base Rock | $20-$45 | 2,800 |
| Landscape Boulders | $100-$300 | 3,000 |
12,800+ estimates calculated this month
Last updated: 2026-03-14
How to Calculate Landscape Rock for Any Project
I've ordered rock for hundreds of landscape beds, drainage swales, and decorative borders over the years. The math is straightforward: area times depth gives you volume, then you convert to tons based on the rock type. Where people get tripped up is the weight conversion. A cubic yard of lava rock weighs about half of what river rock weighs, so you need fewer tons but the same number of cubic yards.
The calculator above does all of that for you. Pick your rock type, plug in your dimensions, and it spits out cubic yards, tons, and a cost range. It handles rectangular and circular areas, multiple zones, and includes landscape fabric and delivery in the estimate.
Inputs you'll need
- Area dimensions - Length and width in feet (or diameter for circular beds and tree rings)
- Rock type - River rock, lava rock, decomposed granite, bull rock, crushed rock, Mexican beach pebbles, or landscape boulders
- Depth - Typically 2-4 inches for landscape beds, 3-6 inches for drainage and erosion control
- Waste factor - 10% is standard for rectangular areas, 15% for irregular shapes
Rock Coverage Reference Table (2026)
| Rock Type | $/Ton | lbs/CY | Coverage at 3" (sq ft/ton) |
|---|---|---|---|
| River Rock (1-3") | $50-$100 | 2,800 | ~77 sq ft |
| Lava Rock | $75-$150 | 1,500 | ~144 sq ft |
| Mexican Beach Pebbles | $200-$500 | 3,000 | ~72 sq ft |
| Decomposed Granite | $25-$50 | 2,800 | ~77 sq ft |
| Bull Rock / Cobble | $45-$90 | 2,600 | ~83 sq ft |
| Crushed Rock / Base | $20-$45 | 2,800 | ~77 sq ft |
Worked examples
Example A: 20x10 landscape bed with river rock at 3 inches
- Area: 20 x 10 = 200 sq ft
- Volume: 200 x (3/12) / 27 = 1.85 cubic yards
- With 10% waste: 2.04 cubic yards
- Weight: 2.04 x 1.4 = 2.85 tons
- Cost (bulk): $143-$285 material + $50-$200 delivery
Example B: 6-foot diameter tree ring with lava rock at 2 inches
- Area: pi x 3^2 = 28.3 sq ft
- Volume: 28.3 x (2/12) / 27 = 0.17 cubic yards
- Weight: 0.19 x 0.75 = 0.14 tons (about 280 lbs)
- Small enough to pick up in bags from a landscape supply yard
Example C: 40x4 drainage swale with bull rock at 4 inches
- Area: 40 x 4 = 160 sq ft
- Volume: 160 x (4/12) / 27 = 1.98 cubic yards
- With 10% waste: 2.17 cubic yards
- Weight: 2.17 x 1.3 = 2.82 tons
- Cost (bulk): $127-$254 material
Figuring other materials? Try our pea gravel calculator for patios and walkways, the gravel calculator for driveways, or the mulch calculator for garden beds around your rock borders.
What I've learned ordering landscape rock
- Order 10% extra. You always lose some rock during spreading and you will find low spots after the first rain. A second delivery for half a ton costs more than just ordering the extra upfront.
- Know your access. A dump truck needs at least 10 feet of clearance width and room to dump. If the truck cannot back up to your bed, you are moving rock by wheelbarrow from the street. Plan accordingly.
- Heavier rock stays put. River rock and bull rock do not wash out in rain the way pea gravel and DG can. For slopes or areas with runoff, go heavier and larger.
- DG compacts 20-25%. If you want 3 inches of finished decomposed granite, spread 4 inches and compact with a plate tamper. It locks into a solid surface that holds up to foot traffic.
- Fabric first, always. I have never seen a rock bed without landscape fabric that did not turn into a weed farm within a year. Spend the extra $0.15-$0.30 per square foot. Cheap fabric breaks down in a season; woven geotextile lasts.
Common ordering mistakes
- Confusing tons and cubic yards. Suppliers sell by the ton, but volume is in cubic yards. A cubic yard of lava rock weighs 0.75 tons, while a cubic yard of river rock weighs 1.4 tons. Same volume, very different weight and price.
- Buying bags for big projects. A 0.5 cu ft bag of river rock at $5-$8 works out to $270-$432 per cubic yard. Bulk delivery is $50-$100 per cubic yard. For anything over about 50 square feet, go bulk.
- Forgetting edging. Rock migrates into lawn, gardens, and driveways without a border. Steel edging ($2-$4/linear foot installed) or a concrete mow strip keeps everything where it belongs.
- Skipping the base. For DG paths and patios, a 2-3 inch compacted base of crusher run underneath keeps the DG from sinking into soft ground. For decorative rock beds, the landscape fabric does this job.
How to Use This Calculator
Select your rock type
Choose from river rock, lava rock, Mexican beach pebbles, decomposed granite, bull rock, crushed rock, or landscape boulders. Each type has different weight and pricing.
Enter your area dimensions
Input length and width for rectangular beds, or diameter for circular tree rings and planter areas. Add multiple areas to calculate the total for your whole project.
Set the depth
The calculator auto-sets a recommended depth for each rock type. Adjust it based on your application. Most landscape rock goes 2-4 inches deep.
Review tons, yards, and cost
See total cubic yards, tons needed, and a cost range based on 2026 bulk pricing. Toggle delivery and landscape fabric to see the full project cost.
Rock Calculation Formulas
Cubic Yards = (Length x Width x Depth in feet) / 27
Tons = Cubic Yards x Weight Factor (varies by rock type)
Coverage (sq ft/ton) = 27 / (Depth in ft x Tons per CY)
Circle Area = pi x (Diameter / 2)^2Where:
- Length, Width
- = Area dimensions in feet
- Depth
- = Rock depth in inches (divide by 12 to convert to feet)
- 27
- = Cubic feet per cubic yard (3 x 3 x 3)
- Weight Factor
- = Tons per cubic yard: river rock 1.4, lava rock 0.75, DG 1.4, bull rock 1.3
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Frequently Asked Questions
How much does landscape rock cost per ton?
Landscape rock prices vary widely by type. Decomposed granite is the cheapest at $25-$50 per ton. River rock runs $50-$100 per ton. Lava rock costs $75-$150 per ton. Mexican beach pebbles are premium at $200-$500 per ton. All prices are for bulk delivery, not bags. Bagged rock from a home improvement store costs 3-5x more per ton.
How many tons of rock do I need per square foot?
At 2 inches deep, most landscape rock covers about 100-130 square feet per ton depending on the rock density. At 3 inches deep, coverage drops to roughly 65-85 square feet per ton. Lighter rocks like lava rock cover more area per ton because they weigh less per cubic yard. The calculator above factors in the weight difference for each rock type.
How deep should landscape rock be?
For most decorative applications, 2-3 inches is the standard depth. Going thinner than 2 inches means the landscape fabric shows through within a season as rocks shift. For drainage areas and erosion control, go 4-6 inches with larger bull rock or cobble. Decomposed granite paths need 3-4 inches because DG compacts down about 25% after settling.
How much does a cubic yard of rock weigh?
It depends on the rock type. River rock and decomposed granite weigh about 2,800 lbs per cubic yard (1.4 tons). Bull rock and cobble weigh around 2,600 lbs per cubic yard. Lava rock is much lighter at roughly 1,500 lbs per cubic yard (0.75 tons) because of its porous structure. This weight difference matters for delivery charges and trailer capacity.
What is the cheapest landscape rock?
Crushed rock or base rock is the cheapest at $20-$45 per ton, but it is not decorative. For visible landscaping, decomposed granite (DG) is the most budget-friendly at $25-$50 per ton. River rock is the most popular mid-range option at $50-$100 per ton. You can also save money by ordering in bulk rather than buying bags.
Do I need landscape fabric under rock?
Yes. Without landscape fabric, rocks sink into the soil and weeds push through within one growing season. Use woven geotextile fabric ($0.15-$0.30/sq ft), not the cheap thin stuff. Overlap seams by 6 inches and pin with landscape staples every 2-3 feet. Skipping fabric is the single most common mistake on rock landscaping projects.
Should I use river rock or pea gravel?
River rock (1-3 inches) stays in place better, does not get kicked around as easily, and looks more natural in landscape beds. Pea gravel (3/8-3/4 inch) is smoother underfoot and better for walkways and patios. Both cost roughly the same per ton. For landscape beds, borders, and drainage, river rock is the better choice. For patios and dog runs, see our pea gravel calculator.
How much rock do I need for a 100 sq ft area?
For river rock at 3 inches deep: you need about 0.93 cubic yards, which is roughly 1.3 tons. Cost is approximately $65-$130 for bulk material. At 2 inches deep, that drops to 0.62 cubic yards (about 0.87 tons) for roughly $43-$87. Add 10% for waste on irregular areas.
How do I calculate rock for a circular area?
Measure the diameter of the circle (edge to edge through the center). The formula is: Area = pi x (diameter / 2)^2. For an 8-foot diameter tree ring: 3.14 x 4^2 = 50.3 square feet. Then multiply by depth and convert to cubic yards. The calculator above handles circular areas automatically.
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