Gravel Calculator — Cubic Yards and Tons
Enter area dimensions and depth to calculate cubic yards and tons of gravel needed. Select gravel type for accurate weight estimates. Includes cost estimate based on current typical pricing.
How to Calculate Gravel
Gravel is ordered by the cubic yard for delivery or by weight (tons) for larger quantities. The formula converts linear dimensions to cubic feet, then to cubic yards, then to weight using the gravel's density.
Gravel Calculation Formula
Volume (cu ft) = Length (ft) × Width (ft) × Depth (in) ÷ 12 Volume (cu yd) = Volume (cu ft) ÷ 27 Weight (lbs) = Volume (cu ft) × Density (lbs/cu ft) Weight (tons) = Weight (lbs) ÷ 2,000
Example: 12 ft × 20 ft driveway, 4 inches deep, crushed stone (110 lbs/cu ft):
Volume = 12 × 20 × (4/12) = 12 × 20 × 0.333 = 80.0 cu ft
= 80.0 ÷ 27 = 2.96 cu yd
Weight = 80.0 × 110 = 8,800 lbs
Tons = 8,800 ÷ 2,000 = 4.40 tons
Cost = 4.40 × $30–$60/ton = $132–$264 Gravel Type Densities
| Gravel Type | Density (lbs/cu ft) | Tons per Cu Yd | Best Use |
|---|---|---|---|
| Pea Gravel | 100 | 1.35 | Pathways, drainage, playground |
| Crushed Stone (#57) | 110 | 1.48 | Driveways, drainage base |
| River Rock | 90 | 1.22 | Decorative, dry creek beds |
| Decomposed Granite | 105 | 1.42 | Pathways, drought landscaping |
| Crusher Run / Base | 115 | 1.55 | Driveway base, compacted fill |
Common Uses and Recommended Depths
| Application | Gravel Type | Depth |
|---|---|---|
| Garden pathway | Pea gravel or decomposed granite | 2–3 inches |
| Driveway (surface layer) | Crushed stone or pea gravel | 2–3 inches |
| Driveway (base layer) | Crusher run / #21A base | 4–6 inches |
| French drain / drainage | Pea gravel or washed stone | Fill trench |
| Decorative landscape bed | River rock or pea gravel | 2–3 inches |
| Under concrete slab | Crushed stone (#57) | 4 inches minimum |
| Septic drain field | Washed angular stone | Per local code |
Drainage Benefits of Gravel
Gravel is a primary tool in landscape drainage management. Unlike compacted soil or clay, gravel maintains air pockets that allow water to percolate rapidly — pea gravel passes water at roughly 500 inches per hour, compared to 0.2 inches per hour for clay soil.
Common drainage applications include:
- French drains: A trench filled with gravel surrounding a perforated pipe diverts groundwater away from foundations and low areas.
- Dry creek beds: River rock arranged in a stream-bed pattern serves as a decorative drainage channel during heavy rain.
- Gravel mulch: In desert and xeriscaping applications, gravel mulch reflects heat, prevents erosion, and requires no replacement.
- Trench drains: Gravel surrounding catch basins and channel drains prevents clogging while allowing water entry.
Ordering and Delivery
Most landscape supply companies deliver a minimum of 1–2 cubic yards. A standard dump truck holds 10–14 cubic yards. Check access to the delivery area — the driver will need clear access and a firm surface to prevent the truck from getting stuck. For large projects, ask about spreading fees (the supplier may spread the gravel with a skid steer for an additional charge). Have the delivery area staked or marked before the truck arrives.
Frequently Asked Questions
How many cubic yards of gravel do I need for a 10×20 driveway at 4 inches deep?
Volume = 10 × 20 × (4/12) ÷ 27 = 10 × 20 × 0.333 ÷ 27 = 66.7 ÷ 27 = 2.47 cubic yards. At 110 lbs/cu ft for crushed stone: 66.7 × 110 = 7,337 lbs = 3.67 tons. Cost estimate at $40/ton: approximately $147.
How deep should a gravel driveway be?
A properly constructed gravel driveway has 3 layers: 4–6 inches of large base rock (2–3" angular crushed stone), 3–4 inches of middle layer (#57 stone or crusher run), and 2–3 inches of top surface layer (pea gravel, crushed stone, or decomposed granite). Total depth is 9–13 inches for a full-build driveway. For light vehicles only, a single 4-inch layer of compacted crusher run on a prepared graded base is the minimum.
What is the difference between pea gravel and crushed stone?
Pea gravel is naturally rounded (river-worn), 3/8" in size, smooth, and easy to walk on. It shifts and rolls underfoot, making it unsuitable for driveways but excellent for pathways and drainage. Crushed stone is quarried and mechanically broken, producing angular pieces that interlock and compact together. For driveways and structural applications, use crushed stone or crusher run. Decomposed granite compacts even better and is ideal for desert landscapes and stable pathways.
How many tons of gravel are in a cubic yard?
It depends on the gravel type: pea gravel is approximately 1.35 tons/cubic yard; crushed stone is approximately 1.48 tons/cubic yard; river rock is approximately 1.22 tons/cubic yard; decomposed granite is approximately 1.42 tons/cubic yard. Density varies by moisture content and exact rock type — these are standard estimates used by most suppliers.
How do I calculate gravel for an irregular area?
For irregular areas, break the space into simpler shapes (rectangles, triangles, circles) and calculate each separately, then sum. For a curved path: estimate average width, measure centerline length, multiply length × width × depth for a rectangle approximation. For circular areas: Volume = π × radius² × depth ÷ 12 (cu ft) ÷ 27 (cu yd). Add 10% to any irregular area estimate to account for edges and uneven distribution.
Related Calculators
- Mulch Calculator — cubic yards and bags of mulch for garden beds
- Concrete Calculator — cubic yards and bags for slabs and columns
- Square Footage Calculator — measure any area shape