Gravel is one of the most versatile landscaping materials out there — driveways, garden paths, drainage beds, and decorative borders all use it. But buying too little means a second run to the store, and buying too much means wasting money on material you'll have to store or haul away. The math isn't complicated, but you do need to know depth, area, and gravel type before you order. Here's everything you need to get it right the first time.
The Gravel Formula (Cubic Yards and Tons)
The standard calculation for gravel volume: (Length ft × Width ft × Depth inches ÷ 12) ÷ 27 = Cubic Yards
To convert cubic yards to tons, multiply by the gravel's density. Most common gravel types run 1.25–1.5 tons per cubic yard. Pea gravel is around 1.4 tons per yard; crushed stone (#57) is closer to 1.5 tons per yard.
Example 1 — Garden path: A 20×3 ft path at 3 inches deep needs (20 × 3 × 3 ÷ 12) ÷ 27 = 0.56 cubic yards. Add 10% buffer → 0.62 yards, or about 0.87 tons of pea gravel.
Example 2 — Residential driveway: A 40×12 ft driveway at 4 inches deep needs (40 × 12 × 4 ÷ 12) ÷ 27 = 5.93 cubic yards. Add 10% → 6.52 yards, or roughly 9.1 tons. At this volume, bulk delivery from a local stone yard is by far the most economical option.
Always add 10% to your final figure. Gravel compacts and settles over time, and low spots appear after the first rain.
How Deep Should Gravel Be?
Depth is the biggest variable most homeowners underestimate. Too shallow and gravel shifts underfoot or under tire pressure; too deep is wasteful and can impede drainage in some applications.
| Project | Depth | Why |
|---|---|---|
| Decorative garden beds / borders | 2 inches | Visual coverage, light weed suppression |
| Walkways / foot-traffic paths | 3 inches | Stable footing, stays in place |
| Residential driveway | 4 inches | Standard for passenger vehicles |
| Base layer under pavers or slabs | 4–6 inches compacted | Structural stability, drainage |
| Heavy-use driveway (trucks, RVs) | 6 inches | Prevents rutting under load |
For driveways specifically, a two-layer approach works better than a single deep layer: 4 inches of compacted #57 crushed stone as the base, then 2 inches of pea gravel or decomposed granite on top. The base layer bears the load; the top layer gives you the clean finished look.
Bags vs. Bulk: What Makes Financial Sense
Bagged gravel at Home Depot or Lowe's typically runs $5–$8 per 0.5 cubic foot bag. One cubic yard is 27 cubic feet, so you'd need 54 bags — that's $270–$430 per cubic yard in bags. Bulk gravel from a landscape or stone supplier runs $25–$65 per ton depending on type and region, or roughly $35–$90 per cubic yard including a local delivery fee of $50–$100.
The break-even point is usually around 1–2 cubic yards. For anything smaller than that — a small garden border or short path — bags are fine. For a driveway or large project, bulk delivery pays for itself quickly. Call two or three local stone yards for quotes before ordering; prices vary significantly by region and material.
Gravel Types and Their Best Uses
Choosing the right gravel type matters as much as getting the quantity right. Each type has different characteristics for drainage, stability, and appearance:
- Pea gravel — Small, smooth, rounded stones (3/8 inch). Comfortable underfoot, great drainage, looks clean. Tends to scatter, so use edging to contain it. Best for pathways, patios, and dog runs.
- Crushed stone (#57) — Angular, irregular pieces that lock together when compacted. The standard choice for driveway base layers and sub-base applications. Less decorative but highly functional.
- Decomposed granite (DG) — Fine, sandy texture that packs firm. Excellent for driveways and paths where you want a stable, dust-free surface. Common in dry climates. Gets muddy in high-rain areas.
- River rock — Smooth, rounded, larger stones (1–3 inches). Decorative, great for drainage swales and dry creek beds. Stays put well due to size. Not comfortable to walk on barefoot.
- Lava rock — Lightweight, porous, and distinctive reddish color. Good for decorative mulching around plants. Retains some heat, so avoid around heat-sensitive plants in hot climates.
- Crushed limestone — Affordable and widely available. Packs well, good for driveways. Can become muddy in wet climates; calcite content raises soil pH over time, which can affect nearby plants.
How Much Does Gravel Cost?
Gravel cost varies by type and whether you buy bagged or in bulk. Here's a general price range for 2026:
| Gravel Type | Bulk (per ton) | Bulk (per cu yd) | Bagged (per 0.5 cu ft bag) |
|---|---|---|---|
| Crushed stone / #57 | $25–$45 | $35–$65 | $5–$7 |
| Pea gravel | $30–$55 | $40–$75 | $5–$8 |
| River rock | $45–$75 | $60–$100 | $6–$9 |
| Decomposed granite | $35–$60 | $45–$80 | $6–$8 |
| Lava rock | $80–$120 | $100–$160 | $8–$12 |
Add $50–$100 for bulk delivery in most markets. Some suppliers offer free delivery above a certain tonnage — ask when you call. For large driveway projects, getting three quotes is worth the time investment.
Tips to Get the Most Out of Your Gravel
A few things that make gravel projects last longer and look better: Install landscape fabric under decorative gravel to block weed growth (unlike mulch, gravel won't suppress weeds on its own — it just covers them temporarily). Use metal or plastic edging around paths and garden beds to prevent scatter. For driveways, a layer of geotextile fabric under the base stone improves long-term stability by preventing the stone from sinking into soft soil.
For pathways, rake gravel level every spring and add a thin top-up layer every 2–3 years as material migrates to the edges or gets kicked out. Most pea gravel paths look their best at 3 inches and need about a half-inch refresh each year to stay looking clean.
Frequently Asked Questions
How many bags of gravel do I need for a 10×10 area at 4 inches deep? A 10×10 ft area at 4 inches needs 1.23 cubic yards (33.3 cubic feet). At 0.5 cubic feet per bag with 10% buffer, that's about 74 bags — bulk delivery is far more practical at this volume.
Does gravel need to be compacted? For driveways and structural base layers, yes — compact each 2–3 inch lift with a plate compactor. Decorative gravel in garden beds doesn't need compaction.
How long does gravel last? Gravel itself doesn't break down, but it migrates, sinks, or gets contaminated with soil over time. Driveway gravel typically needs replenishment every 2–5 years. Decorative path gravel may need a top-up every 1–2 years.