Landscape Rock Calculator
Use this free landscape rock calculator to instantly calculate how much rock you need — in tons, cubic yards, or 50 lb bags — for flower beds, pathways, driveways, dry creek beds, and decorative borders. Covers 7 rock types including pea gravel, river rock, lava rock, decomposed granite, crushed stone, marble chips, and flagstone — each with accurate density-based weight conversion.
2 inches is the minimum recommended depth for weed suppression with landscape fabric · Lava rock is lightest (0.8 t/cu yd) · Decomposed granite compacts — order 15% extra · Always install landscape fabric underneath · Bulk delivery beats bags for projects over 1 cu yd
Estimates based on 2026 US average pricing from landscape suppliers and HomeAdvisor data. Rock density values from industry standard bulk material data. Always confirm current pricing with your local landscape supplier.
How Does the Landscape Rock Calculator Work?
This calculator estimates how much rock you need in tons, cubic yards, or 50 lb bags for any landscaping project — flower beds, pathways, driveways, dry creek beds, and decorative borders. It uses the actual density of each rock type for accurate tonnage calculations, since rock sold by weight (tons) varies significantly between types: lava rock weighs less than half as much per cubic yard as decomposed granite.
How to Use
- Enter your area length and width in feet. For irregular shapes, use our Square Footage Calculator to find your total area first.
- Select your desired depth — 2 inches is recommended for most decorative applications with landscape fabric installed.
- Select your rock type — each type has a different density, which affects weight and cost significantly.
- Choose your preferred unit — tons for bulk delivery, cubic yards for volume orders, bags for small projects.
- Select a waste factor — 10% is recommended to account for settling and irregular edges.
Install landscape fabric (weed barrier) under all decorative rock. Without it, weeds push through rock within 1–2 seasons and removing rock to re-weed is a miserable job. Use commercial-grade woven geotextile fabric — not cheap black plastic sheeting. Commercial fabric costs $0.10–$0.20 per sq ft and lasts 15–20 years. Overlap seams by at least 6 inches and pin every 12 inches.
3 Worked Examples
Example 1 — Flower Bed (20×10 ft, River Rock, 3 Inches)
A 200 sq ft front yard flower bed redesign with river rock at 3-inch depth for effective weed suppression. 10% waste factor, bulk delivery.
20 × 10 = 200 sq ft
Step 2 — Volume in cu ft:200 × (3 ÷ 12) = 200 × 0.25 = 50 cu ft
Step 3 — Cubic yards with 10% waste:(50 ÷ 27) × 1.10 = 1.85 × 1.10 = 2.04 cu yd
Step 4 — Tons (river rock = 1.35 t/cu yd):2.04 × 1.35 = 2.75 tons
| Item | Qty | Unit Cost | Total |
|---|---|---|---|
| River rock (bulk delivery) | 2.75 tons | $45–$130/ton | $124–$358 |
| Delivery charge | 1 load | $50–$150 | $50–$150 |
| Landscape fabric (woven geotextile) | 220 sq ft (+10%) | $0.10–$0.20/sq ft | $22–$44 |
| Landscape fabric pins | 30 pins | $0.15–$0.30 each | $5–$9 |
| Metal or plastic edging (60 linear ft) | 60 LF | $0.50–$2.00/LF | $30–$120 |
| Total materials | $231–$681 | ||
Real-world note: River rock varies enormously in price by region — in areas with local quarries it can be as low as $30/ton; in coastal markets with no local stone, $120+/ton is common. Always get 3 quotes from local landscape supply yards. Smooth river rock is visually striking but rolls underfoot — if this bed has a path through it, consider angular pea gravel or crushed stone for the walking area.
Example 2 — Decomposed Granite Pathway (50×4 ft, 3 Inches)
A 200 sq ft decomposed granite pathway through a side yard. 3-inch depth for stability, 15% waste (DG compacts and some material is lost at edges), with stabilizing polymer binder.
50 × 4 = 200 sq ft
Step 2 — Volume with 15% waste:(200 × 0.25 ÷ 27) × 1.15 = 1.85 × 1.15 = 2.13 cu yd
Step 3 — Tons (DG = 1.5 t/cu yd):2.13 × 1.50 = 3.19 tons
| Item | Qty | Unit Cost | Total |
|---|---|---|---|
| Decomposed granite (bulk) | 3.19 tons | $30–$70/ton | $96–$223 |
| Stabilizing polymer binder | 2 bags (covers ~200 sq ft) | $30–$50/bag | $60–$100 |
| Delivery | 1 load | $50–$150 | $50–$150 |
| Landscape fabric | 230 sq ft | $0.10–$0.20/sq ft | $23–$46 |
| Edging (108 linear ft perimeter) | 108 LF | $0.50–$2.00/LF | $54–$216 |
| Total materials | $283–$735 | ||
Real-world note: Unstabilized decomposed granite tracks into the house on shoe soles, erodes in rain, and develops ruts in high-traffic areas within 1–2 seasons. For any pathway, the stabilizing polymer binder is worth the extra $60–$100 — stabilized DG compacts firm, resists erosion, stays in place, and still allows water to percolate through. Compact in 2-inch lifts with a plate compactor or hand tamper, not all at once. Most equipment rental yards rent plate compactors for $60–$80/day.
Example 3 — Dry Creek Bed (60×3 ft, River Rock Mix, 6 Inches)
A decorative dry creek bed across a low area with drainage issues — 180 sq ft at 6-inch depth using a mix of small and large river rock. 15% waste for irregular shape and multiple rock sizes.
60 × 3 = 180 sq ft
Step 2 — Volume with 15% waste:(180 × 0.50 ÷ 27) × 1.15 = 3.33 × 1.15 = 3.83 cu yd
Step 3 — Tons (river rock = 1.35 t/cu yd):3.83 × 1.35 = 5.17 tons
| Item | Qty | Unit Cost | Total |
|---|---|---|---|
| Small river rock (1" — creek fill) | 3.0 tons (60%) | $45–$130/ton | $135–$390 |
| Large river rock (3"–5" — accent boulders) | 2.17 tons (40%) | $60–$150/ton | $130–$326 |
| Delivery (2 loads for size mix) | 2 loads | $50–$150/load | $100–$300 |
| Landscape fabric (20" wide, 70 LF) | 200 sq ft | $0.10–$0.20/sq ft | $20–$40 |
| Total materials | $385–$1,056 | ||
Real-world note: A dry creek bed that handles real drainage requires more than just rocks on fabric — the underlying soil must slope away from the house at least 1/4 inch per foot. Without proper grading, the creek bed just holds water. Mix rock sizes for a natural look: 60% smaller fill rock and 40% larger accent rocks. Line the bed with landscape fabric before filling to prevent the smaller rocks from sinking into the soil. This project may require a permit if it redirects stormwater off your property — check with your municipality before digging.
Landscape Rock Types Guide
Different rock types serve different purposes. Choosing the right rock affects appearance, maintenance, cost, and functionality dramatically.
| Rock Type | Size | Cost/Ton | Best For | Notes |
|---|---|---|---|---|
| Pea Gravel | ⅜ inch | $25–$55 | Pathways, playgrounds, borders | Round, comfortable underfoot |
| River Rock | 1–5 inches | $45–$130 | Dry creek beds, drainage, accents | Smooth, decorative, various colors |
| Lava Rock | ½–2 inches | $75–$200 | Flower beds, moisture retention | Very light, good insulation |
| Decomposed Granite | Fine | $30–$70 | Pathways, driveways, xeriscaping | Compacts firm, stabilizer available |
| Crushed Stone / Limestone | ¾ inch | $25–$55 | Driveways, drainage, base layer | Angular, locks together, alkaline |
| Marble Chips | ½–1 inch | $60–$150 | Formal gardens, accent beds | White/cream; raises soil pH — avoid near acid-loving plants |
| Flagstone | Irregular slabs | $200–$600 | Patios, stepping stones, paths | Natural, requires leveling |
| Quartzite / White Stone | 1–3 inches | $75–$180 | Modern landscapes, pool areas | Bright white, high-end look |
Lava rock is significantly lighter than pea gravel — about 0.8 tons per cubic yard vs 1.4 tons. You order less by weight but get the same coverage. Lava rock also retains moisture better around plants and insulates roots from heat. However it costs more per ton, fades over time, and can look dated in certain styles. Pea gravel is more versatile and timeless. Avoid marble chips near acid-loving plants like azaleas — marble is alkaline and raises soil pH over time.
Recommended Rock Depth by Application
Depth directly affects weed suppression, appearance, and total material cost. Too shallow and weeds push through. Too deep and you waste money.
| Application | Recommended Depth | Notes |
|---|---|---|
| Decorative flower beds | 2 inches | Minimum for weed suppression with fabric |
| Garden borders | 2–3 inches | Deeper for better weed control without fabric |
| Walkways / paths | 3–4 inches | Deep enough to stay stable underfoot |
| Driveways (pea gravel) | 4–6 inches | Needs edging to prevent migration |
| Dry creek beds | 4–6 inches | Use multiple sizes for natural look |
| Drainage areas | 6–12 inches | Depth depends on drainage volume |
| Playground safety surface | 6–9 inches | CPSC standard for fall safety at 6 ft equipment height |
Landscape Rock Coverage Chart
Quick reference for common project sizes using pea gravel (1.4 tons/cu yd) at various depths with 10% waste factor.
| Area | 2 inch depth | 3 inch depth | 4 inch depth |
|---|---|---|---|
| 100 sq ft | 0.64 tons / 0.46 cu yd | 0.96 tons / 0.69 cu yd | 1.27 tons / 0.91 cu yd |
| 200 sq ft | 1.27 tons / 0.91 cu yd | 1.91 tons / 1.36 cu yd | 2.55 tons / 1.82 cu yd |
| 500 sq ft | 3.18 tons / 2.27 cu yd | 4.77 tons / 3.41 cu yd | 6.36 tons / 4.54 cu yd |
| 1,000 sq ft | 6.36 tons / 4.54 cu yd | 9.54 tons / 6.81 cu yd | 12.72 tons / 9.09 cu yd |
| 2,000 sq ft | 12.72 tons / 9.09 cu yd | 19.07 tons / 13.62 cu yd | 25.43 tons / 18.17 cu yd |
Based on pea gravel density (1.4 tons/cu yd) with 10% waste. Lava rock weighs ~40% less per cubic yard. Use the calculator above for other rock types.
Landscape Rock Cost (2026)
| Rock Type | Per Ton (bulk) | Per Cu Yd | Per 50 lb Bag |
|---|---|---|---|
| Pea Gravel | $25–$55 | $35–$77 | $4–$8 |
| Crushed Stone / Limestone | $25–$55 | $36–$80 | $4–$7 |
| Decomposed Granite | $30–$70 | $45–$105 | $5–$10 |
| River Rock | $45–$130 | $61–$176 | $6–$12 |
| Lava Rock | $75–$200 | $60–$160 | $8–$18 |
| Marble Chips | $60–$150 | $84–$210 | $8–$16 |
| Delivery (bulk) | $50–$150 per load | — | |
Bagged rock from home improvement stores costs 3–5× more per ton than bulk delivery. For any project over 1 cubic yard (about 1.4 tons of pea gravel), bulk delivery is cheaper even after the delivery fee. For projects under 0.5 cubic yards, bags may be more practical than a delivery minimum. Use the Pea Gravel Calculator for detailed pea gravel bag and bulk pricing.
Common Calculation Mistakes
Ordering by Volume Without Accounting for Rock Density
The most common mistake: ordering the same cubic yards of lava rock and river rock and expecting the same price. Lava rock weighs 0.8 tons per cubic yard; river rock weighs 1.35 tons per cubic yard — nearly 70% more. Since bulk rock is priced by weight (tons), the same volume of different rock types can cost dramatically different amounts. Always convert to tons using the actual density before comparing supplier quotes.
Using Too Little Depth
Homeowners frequently underestimate depth to save on material costs. Installing rock at 1 inch instead of the recommended 2 inches looks thin, settles to less than an inch within months, and provides zero weed suppression — requiring a re-application in year 2. The difference between 1 inch and 2 inches is exactly double the material cost, but the difference in effectiveness is not linear. Always use at least 2 inches with landscape fabric.
Forgetting Landscape Fabric and Edging in the Material List
A material list that includes only rock will result in a project that costs 20–40% more than expected once fabric, pins, and edging are added. For a 200 sq ft project, rock alone might be $120. Fabric + pins + edging adds $55–$225. The complete material list is significantly more than the rock alone. Always build a complete list before ordering.
Not Adding Extra for Irregular Shapes and Slopes
The calculator uses a rectangular area calculation (length × width). For irregular beds with curves, peninsulas, or slopes, simply multiplying the bounding rectangle overestimates area — but the waste that’s genuinely lost in fitting rock to curves and slopes means you still need the full amount. Use the 15–20% waste factor for any bed that isn’t a simple rectangle, and measure the actual perimeter carefully for edging.
Ordering Bags When Bulk Is Significantly Cheaper
A 50 lb bag of pea gravel at $6 equals $240/ton. Bulk pea gravel delivered runs $25–$55/ton. For any project over 1 cubic yard (~1.4 tons of pea gravel), bulk delivery is 4–10× cheaper even including the delivery fee. The convenience of bags is real — no waiting for delivery, no truck access needed, carry it in your car. But for projects over 0.5 cubic yards, do the math before defaulting to bags.
Buying & Installation Tips
Before You Order
- Get 3 quotes from local suppliers — landscape rock pricing varies enormously by region and supplier. Call local quarries, landscape supply yards, and big box stores to compare.
- Ask about delivery minimums — most bulk suppliers have a 1–3 ton minimum for delivery. Factor the delivery fee into your per-ton cost comparison.
- Order a sample bag first — color, size, and texture can look very different in person vs website photos. Buy a small bag from a local store before committing to a full bulk order.
- Check truck access — bulk delivery trucks need clear access and typically dump the load at the curb or driveway. Plan where the pile will go before ordering.
Installation Tips
- Install landscape fabric first — overlap seams by at least 6 inches and pin every 12 inches. Fold fabric up against edging to prevent rock migration underneath.
- Install edging before rock — metal, plastic, or rubber edging keeps rock contained and prevents migration into lawn areas.
- Spread evenly with a landscaping rake — check depth with a ruler in multiple spots to ensure consistency.
- Keep rock away from plant stems — leave a 2–3 inch gap around tree trunks and plant stems to prevent moisture buildup and rot.
If using decomposed granite for pathways, add a stabilizing polymer binder mixed in before compacting. Stabilized DG sets almost like a permeable concrete — it resists erosion, doesn’t track into the house, and stays firm underfoot. It costs $30–$50 extra for a standard pathway but is worth every penny for high-traffic areas. Compact in 2-inch lifts with a plate compactor ($60–$80/day rental) for a durable result.
How We Calculate
Volume (cu ft) = Length × Width × (Depth ÷ 12) · Cubic Yards = (Volume ÷ 27) × Waste Factor · Tons = Cubic Yards × Rock Density (tons/cu yd)
The density constants used in the calculator — pea gravel 1.40 t/cu yd, lava rock 0.80 t/cu yd, river rock 1.35 t/cu yd, decomposed granite 1.50 t/cu yd, crushed stone 1.45 t/cu yd, marble chips 1.40 t/cu yd, flagstone 1.50 t/cu yd — are based on bulk material weight data from landscape supply industry sources and are consistent with values published by major US aggregate suppliers.
Bag count is calculated as: CEILING(Tons × 2,000 lb/ton ÷ 50 lb per bag). The 10% default waste factor accounts for settling, edge overage, and irregular bed shapes. Use 15–20% for slopes, curved beds, or complex obstacles. Cost ranges reflect 2026 US national average pricing from landscape supply yard data and HomeAdvisor completed project reports.
Frequently Asked Questions
- CPSC (US Consumer Product Safety Commission) — Public Playground Safety Handbook — Playground safety surface depth requirements for loose-fill materials including pea gravel: minimum 9 inches of uncompressed loose fill for equipment at 6 ft use zone height (Publication #325). Referenced for playground depth guidance in the recommended depth table. US CPSC, current edition.
- Aggregate Industry Weight Data — Bulk Material Density Constants — Density values used in the calculator: pea gravel 1.40 t/cu yd, lava rock 0.80 t/cu yd, river rock 1.35 t/cu yd, decomposed granite 1.50 t/cu yd, crushed limestone 1.45 t/cu yd, marble chips 1.40 t/cu yd, flagstone 1.50 t/cu yd. Consistent with values from major US aggregate suppliers and ASTM C136 gradation data. Landscape supply industry standard bulk material data.
- HomeAdvisor True Cost Guide 2026 — Landscape rock pricing by material type and US region, delivery fee data, and installed landscape rock project cost ranges. Referenced for all cost estimates in the cost table, worked examples, and hidden costs section. HomeAdvisor / Angi, 2026.
- RSMeans Building Construction Cost Data 2026 — Labor cost data for landscape rock installation and edging by material type and project size. Referenced for labor cost estimates in the worked examples. RSMeans / Gordian, 2026.
- International Erosion Control Association (IECA) — Landscape Fabric / Geotextile Specifications — Performance requirements for woven geotextile landscape fabric (water flow rate, tensile strength, UV stability) and overlap/pinning guidance. Referenced for the landscape fabric guidance in the hidden costs and installation tips sections. IECA, current edition.
Rock pricing reflects 2026 US national average pricing from landscape supply yards. Pricing varies significantly by region — areas near local quarries pay substantially less per ton than markets reliant on shipped stone. Always get 3 local quotes before ordering any bulk rock delivery. ConstructlyTools does not have a paid relationship with any landscape rock supplier or contractor mentioned on this page.