How Much Gravel Do I Need? (Calculator + Tons)
Quick answer: length × width × depth (feet) ÷ 27 = cubic yards, then × ~1.4 tons per yard for weight. A 20×10 ft driveway at 4 in deep needs about 2.5 cubic yards ≈ 3.5 tons. Here's the full method.
- Gravel volume formula
- Depth by use
- Yards to tons
- Worked example
- Ordering tips
- Common mistakes
Gravel volume formula
Gravel is ordered by the cubic yard and often priced by the ton. Work in feet:
Length (ft) × Width (ft) × Depth (ft) ÷ 27 = cubic yards. Convert depth from inches first: 4 in = 0.333 ft, 2 in = 0.167 ft.
Depth by use
| Project | Recommended depth |
|---|---|
| Mulch-like bed / path | 2 in |
| Walkways | 3 in |
| Driveways (compact) | 4–6 in |
| Base under pavers | 4 in (compacted) |
Yards to tons
Gravel density varies, but a common figure is 1.4 tons per cubic yard for typical driveway gravel. So yards × 1.4 ≈ tons. Ask your supplier for their exact weight per yard — different rock sizes and moisture change it.
Worked example
- Area = 20 × 10 = 200 sq ft
- Depth = 4 in = 0.333 ft
- Volume = 200 × 0.333 = 66.6 cu ft
- Cubic yards = 66.6 ÷ 27 = 2.47 cu yd
- Tons = 2.47 × 1.4 ≈ 3.5 tons
Ordering tips
Gravel compacts, so order a little extra (5–10%) to top up after settling. A delivery minimum often applies — a single ton may cost more per yard than a larger load. For a paver base, account for two layers: coarse base then fine bedding sand.
Quick lookup: common projects
Here's what common gravel jobs need (with a little extra included):
| Project | Depth | Cubic yards | Tons (approx) |
|---|---|---|---|
| 4×10 path | 3 in | 0.4 | ~0.6 |
| 10×10 pad | 4 in | 1.2 | ~1.7 |
| 20×10 driveway | 4 in | 2.5 | ~3.5 |
| 20×20 driveway | 6 in | 7.4 | ~10.4 |
| Base under 200 sq ft of pavers | 4 in | 2.5 | ~3.5 |
Gravel types & what they cost
The right rock depends on the job. Crushed stone / driveway gravel (often #57 or #67) compacts well for driveways and bases. Pea gravel is round and comfortable underfoot, good for paths and play areas, but it shifts and doesn't compact. River rock is decorative but loose. Drainage stone (larger, angular) is for French drains and backfill. Bulk gravel runs roughly $25–$60 per ton delivered in 2026, plus delivery; small loads often pay a delivery minimum.
Layers: base vs top course
Most gravel driveways aren't a single layer. A typical build is a coarse crushed-stone base (compacted, often 4–6 in) topped with a finer, more comfortable top course. For pavers, you need a compacted gravel base plus a thin layer of bedding sand before the pavers. Skipping the base is why gravel paths sink and spread within a season.
FAQ
A 20×10 ft driveway at 4 inches deep needs about 2.5 cubic yards, or roughly 3.5 tons. Add 5–10% for settling and compaction, and layer a coarse base with a finer top course.
Typically about 1.4 tons per cubic yard for common driveway gravel. Density varies by rock size and moisture, so confirm the exact weight per yard with your supplier.
Crushed stone is angular and compacts well, ideal for driveways and bases. Pea gravel is round, comfortable underfoot, and good for paths, but it shifts and doesn't compact into a firm surface.
About 4–6 inches of compacted gravel for car traffic, often built as a coarse base with a finer top course. For light paths, 2–3 inches is enough.
Common mistakes
- Converting depth wrong. Inches to feet is critical — 4 in is 0.333 ft, not 4 ft.
- Mixing gravel with the base layers. A driveway often needs crushed stone base plus a finer top course.
- Under-ordering. Gravel settles up to 10% — buy extra.
- Ignoring delivery minimums. Check before you calculate the final order size.