How Much Gravel Do I Need?
Enter your project dimensions and gravel depth to calculate cubic yards, tons, and bags needed — instantly. Works for driveways, paths, garden beds, and drainage projects.
How to Calculate Gravel Needed
The formula: (Length ft × Width ft × Depth inches ÷ 12) ÷ 27 = Cubic Yards
Multiply length by width to get square footage, multiply by depth in feet (depth in inches ÷ 12), then divide by 27 to convert cubic feet to cubic yards. For weight, multiply cubic yards by the gravel's density — typically 1.25–1.5 tons per cubic yard depending on type. Always add 10% to account for compaction and settling after the first rain.
Example: a 20×10 ft driveway at 4 inches deep = 20 × 10 × (4/12) / 27 = 2.47 cubic yards. With 10% buffer: 2.72 cubic yards, or roughly 3.8 tons of crushed stone.
Recommended Gravel Depth by Project
| Project Type | Recommended Depth | Notes |
|---|---|---|
| Garden beds / borders | 2 inches | Decorative cover, weed suppression |
| Walkways / paths | 3 inches | Stable footing, light foot traffic |
| Residential driveway | 4 inches | Standard passenger vehicles |
| Base layer under pavers | 4–6 inches | Compacted, then topped with sand |
| Heavy-duty driveway | 6 inches | Trucks, RVs, frequent use |
| French drain / drainage | 6–12 inches | Use washed stone or #57 |
Gravel Coverage Quick Reference
| Area (sq ft) | 2\" Deep (cu yd) | 3\" Deep (cu yd) | 4\" Deep (cu yd) | 4\" Deep (tons) |
|---|---|---|---|---|
| 50 sq ft | 0.31 | 0.46 | 0.62 | ~0.9 tons |
| 100 sq ft | 0.62 | 0.93 | 1.23 | ~1.7 tons |
| 200 sq ft | 1.23 | 1.85 | 2.47 | ~3.5 tons |
| 500 sq ft | 3.09 | 4.63 | 6.17 | ~8.6 tons |
| 1,000 sq ft | 6.17 | 9.26 | 12.35 | ~17.3 tons |
| 2,000 sq ft | 12.35 | 18.52 | 24.69 | ~34.6 tons |
One bulk cubic yard covers approximately 162 sq ft at 2 inches, 108 sq ft at 3 inches, or 81 sq ft at 4 inches.
Gravel Types and Best Uses
| Type | Best For | Density (tons/yd³) | Notes |
|---|---|---|---|
| Pea Gravel | Garden beds, playgrounds, paths | ~1.4 | Smooth, rounded; shifts underfoot |
| Crushed Stone (#57) | Driveways, drainage, base layers | ~1.5 | Angular; compacts and locks together |
| River Rock | Decorative beds, drainage | ~1.35 | Rounded, polished; higher cost |
| Decomposed Granite | Pathways, patios, desert landscaping | ~1.5 | Fines compact into firm surface |
| Lava Rock | Decorative, xeriscape | ~1.25 | Lightweight; retains heat, resists weeds |
| #411 / Dense Grade | Driveway base, parking pads | ~1.5 | Mix of stones and fines; best base material |
Bags vs. Bulk: Which Is Cheaper?
For small projects under 0.5 cubic yards, bags are convenient and often cheaper when you factor in delivery minimums. For anything larger, bulk almost always wins.
| Method | Unit Size | Approx. Cost | Best For |
|---|---|---|---|
| Bagged (0.5 cu ft) | 0.5 cubic feet | $4–$7/bag | Small fills under 0.5 cu yd |
| Bagged (0.5 cu ft) | Equivalent to 1 cu yd | $215–$375 | No bulk supplier nearby |
| Bulk delivery | Per cubic yard | $35–$75/yd³ + delivery | Projects over 1 cu yd |
| Bulk pickup | Per ton | $25–$55/ton | Best unit cost with a truck |
A cubic yard of pea gravel from a landscape supplier costs $35–$75. The same volume in 0.5 cu ft bags runs $215–$375. If you can rent a pickup truck or have delivery available, bulk is the clear winner for any project over a cubic yard.
Frequently Asked Questions
How many tons of gravel do I need for a driveway?
At a 3-inch depth, gravel covers roughly 65-80 sq ft per ton. A typical 20x40 ft (800 sq ft) driveway needs about 8-10 tons.
How deep should gravel be for a driveway?
A driveway base layer should be at least 4-6 inches deep, with an additional 2-inch top layer of finer gravel, for a total of 6-8 inches.
How much does a ton of gravel cover?
One ton covers roughly 100 sq ft at 2 inches deep, or 65-80 sq ft at 3 inches deep — coverage drops as depth increases.
What's the difference between crushed stone and gravel?
Crushed stone has angular edges that lock together for a stable base. Natural gravel is rounded and compacts less firmly, making it better for decorative or drainage uses than load-bearing driveways.