How to Calculate Gravel
To determine how much gravel you need, you first measure the length and width of the area to be covered, and decide on the depth (or thickness) of the gravel layer.
Formula:
Area (sq ft) = Length (ft) × Width (ft)
Volume (cubic feet) = Area (sq ft) × (Depth in inches ÷ 12)
Volume (cubic yards) = Volume (cubic feet) ÷ 27
Weight (tons) = Volume (cubic yards) × Material Density (tons/yd³)
Example Calculation
A new driveway section is 20 ft long and 10 ft wide. You want a 2-inch layer of pea gravel.
- Area: 20 × 10 = 200 sq ft
- Depth in feet: 2 / 12 = 0.166 ft
- Volume in cubic feet: 200 × 0.166 = 33.3 cubic ft
- Cubic yards: 33.3 / 27 = 1.23 cubic yards
If you choose Pea Gravel (which weighs about 1.4 tons per cubic yard), the weight would be 1.23 × 1.4 = 1.72 tons. A 10% waste factor is usually added.
How Much Should I Buy?
When ordering gravel, it is standard practice to round up to the nearest half or whole cubic yard or ton, and include a 5% to 10% waste factor. Gravel settles into the dirt below, and some is lost during spreading.
Frequently Asked Questions
How much gravel do I need?
Measure your area and decide on the depth. A typical driveway requires 4 to 8 inches of gravel depending on the subgrade, while a decorative landscaping bed might only need 2 inches. Use our gravel calculator to convert those dimensions into tons or cubic yards.
How many tons of gravel are in a cubic yard?
This depends on the type of gravel and its moisture content. On average, a cubic yard of gravel weighs between 1.2 and 1.5 tons. For example, crushed stone is typically 1.35 tons per yard, while river rock can be 1.5 tons.
Do I buy gravel by the ton or the yard?
It depends on your local supplier. Quarries and large suppliers typically sell and weigh material by the ton, while smaller landscape supply centers might load a skid steer bucket measured by the cubic yard.
Should I use a weed barrier under the gravel?
For decorative landscaping beds and walkways, a high-quality weed barrier (landscape fabric) is highly recommended. For driveways, a heavy-duty geotextile fabric helps prevent the gravel from sinking into the mud.