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.
Cubic Yards = Volume ÷ 27 · Tons = Cu Yd × Density (tons/cu yd)
50 lb Bags = (Tons × 2,000) ÷ 50
2 inches is the minimum recommended depth for weed suppression · Lava rock is lightest · Decomposed granite compacts; order 15% extra · Always use landscape fabric underneath
Estimates based on 2026 US average pricing. Always confirm current pricing with your local landscape supplier.
How Does the Landscape Rock Calculator Work?
This landscape rock 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.
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.
- Select your rock type — each rock has a different density, which affects weight 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 fabric — not the cheap black plastic sheeting. Commercial fabric costs $0.10–$0.20 per sq ft and lasts 15–20 years.
Landscape Rock Types Guide
Different rock types serve different purposes in landscaping. Choosing the right rock dramatically affects appearance, maintenance, cost, and functionality.
| 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 |
| Marble Chips | ½–1 inch | $60 – $150 | Formal gardens, accent beds | White/cream, elegant appearance |
| 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. This means 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. Pea gravel is more versatile and timeless.
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 on material.
| 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 |
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). 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.
Example Calculation
You want to cover a 20×10 ft flower bed with river rock at 3 inches deep with 10% waste factor.
20 × 10 = 200 sq ft
Step 2 — Volume in cubic feet:200 × (3 ÷ 12) = 200 × 0.25 = 50 cu ft
Step 3 — Convert to cubic yards:50 ÷ 27 = 1.85 cu yd
Step 4 — Add 10% waste:1.85 × 1.10 = 2.04 cu yd to order
Step 5 — Convert to tons (river rock = 1.35 tons/cu yd):2.04 × 1.35 = 2.75 tons
Step 6 — Cost estimate (river rock at $80/ton avg):2.75 × $80 = ~$220 in materials + delivery
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 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 it from migrating into lawn areas. See our Gravel Driveway Guide for edging installation tips.
- Spread evenly with a rake — use a landscaping rake to spread rock to an even depth. Check depth with a ruler in multiple spots.
- Keep rock away from plant stems — don't pile rock directly against tree trunks or plant stems. Leave a 2–3 inch gap to prevent moisture buildup and rot.
If using decomposed granite for pathways, consider adding a stabilizing polymer binder mixed into the DG 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 about $30–$50 extra for a standard pathway but is worth every penny for high-traffic areas.