Use our free rock calculator to estimate cubic yards, tons, and cost for landscaping rock, gravel, and crushed stone. Enter your area and depth — get instant results, no signup needed.
👤 Who is this for: landscapers, garden designers & DIY curb-appeal projects.
How to Calculate Rock Needed
Length (ft) × Width (ft) × Depth (in) ÷ 324 = cubic yards. To get tons, multiply cubic yards by ~1.4 (typical for gravel and crushed stone).
Example: a 20×10 ft driveway at 3 inches deep = 200 × 3 ÷ 324 = 1.85 cubic yards ≈ 2.6 tons of rock.
Rock Coverage — What 1 Cubic Yard Covers
| Depth | Coverage |
|---|---|
| 2 inches | 162 sq ft |
| 3 inches | 108 sq ft |
| 4 inches | 81 sq ft |
| 6 inches | 54 sq ft |
Rock Types & Weights (per cubic yard)
- Pea gravel: ~1.3 tons
- Crushed stone: ~1.4 tons
- River rock: ~1.4 tons
- Lava rock: ~0.65 tons (lightweight)
📝 Real Project Example
20×5 ft bed, 3 inches of river rock:
- Area: 100 sq ft
- Volume: 100 × 0.25 = 25 cu ft
- Cubic yards: 25 ÷ 27 = 0.93 → order 1 cubic yard
- Weight: 0.93 × 1.4 = ~1.3 tons — a pickup bed handles it
- Cost check: 1 cubic yard decorative river rock at ~$80–$120 = ~$100
Lay landscape fabric first — it stops weeds and keeps rock from sinking into soil. Lava rock is the lightweight exception at ~0.65 tons per yard.
📚 Sources & Methodology
How we calculate. Step 1: volume in cubic feet = length × width × depth (all in feet). Step 2: cubic yards = cubic feet ÷ 27. Step 3: tons = cubic yards × 1.4 (river rock/crushed stone; pea gravel ~1.3, lava rock ~0.65). We recommend 2–3 inches for decorative cover.
Cross-checked. Our weight figures match published aggregate density references; decorative rock is sold by the yard but priced well above base gravel.
Sources:
- Ergeon — Gravel Calculator (aggregate density 1.28–1.42 tons per cubic yard)
- The Calculator Site — How Much Does a Cubic Yard Weigh? (gravel 2,300–2,900 lbs per cubic yard)
Last updated: October 2026.