River Rock Calculator
Calculate how much river rock you need for landscaping, garden beds, pathways, drainage areas, and other projects. Get estimated cubic yards, cubic feet, tons, bags, coverage, and material cost.
Calculate river rock
Enter the size of your area, choose a river rock size and depth, and get an estimate of the material required.
About 33.3 cubic feet.
Based on the entered price per ton.
This is an estimate. Actual river rock weight and coverage can vary depending on rock size, density, shape, depth, and how the material is installed.
How to use the river rock calculator
This river rock calculator helps you estimate how much decorative stone you need for landscaping, garden beds, pathways, drainage areas, borders, and other outdoor projects.
- Measure the length of the area.
- Measure the width of the area.
- Enter the desired river rock depth.
- Select the approximate rock size.
- Check the material density or adjust it using your supplier's information.
- Optionally enter the price per ton.
- Click Calculate river rock.
The calculator estimates the volume in cubic yards and cubic feet, approximate weight in tons, coverage, and material cost.
How much river rock do I need?
The amount of river rock you need depends on the size of the area and how deep you want the rock layer to be. A larger area requires more material, while increasing the depth also increases the amount required.
For example, a 20-foot by 10-foot landscaping area is 200 square feet. At a depth of 2 inches, the required volume is approximately 33.3 cubic feet, or 1.23 cubic yards.
Your actual quantity may be different because river rock varies in size, density, shape, and how tightly the pieces settle together.
How to calculate how much river rock I need
To calculate river rock, multiply the length by the width and then multiply the area by the desired rock depth.
If the depth is measured in inches, divide it by 12 to convert the depth into feet.
To convert the result into cubic yards, divide the cubic-foot volume by 27.
2 inch river rock calculator
A 2-inch layer is a useful starting point for many decorative river rock landscaping projects. The exact depth you need depends on the application, rock size, ground conditions, and your desired appearance.
To calculate a 2-inch layer, convert 2 inches to feet:
Then multiply the area by 0.1667 feet to calculate the approximate volume required.
For example, a 300-square-foot area at 2 inches deep requires:
That is approximately 1.85 cubic yards of river rock.
River rock coverage calculator
River rock coverage depends on the amount of material and the depth at which it is installed. A thinner layer covers more square feet, while a deeper layer covers less area.
One cubic yard contains 27 cubic feet. At a depth of 2 inches, one cubic yard theoretically covers approximately:
Therefore, one cubic yard can cover about 162 square feet at a 2-inch depth under ideal conditions.
Actual coverage can vary because river rocks are irregularly shaped and do not form a perfectly uniform layer.
How much river rock does one yard cover?
The answer depends on the depth. One cubic yard contains 27 cubic feet, so the coverage changes as the depth changes.
Approximate theoretical coverage for different depths is:
- 1 inch: about 324 square feet per cubic yard
- 2 inches: about 162 square feet per cubic yard
- 3 inches: about 108 square feet per cubic yard
- 4 inches: about 81 square feet per cubic yard
These are volume-based estimates. Real-world coverage can differ because river rock pieces vary in size and shape and may settle differently.
How many yards of river rock do I need?
Once you know the cubic feet required, divide the result by 27 to determine the number of cubic yards.
For example, if your project requires 81 cubic feet:
You would therefore need approximately 3 cubic yards of river rock, before allowing for any additional material you may want for uneven ground or installation waste.
How much does a yard of river rock weigh?
The weight of a cubic yard of river rock depends on the density of the particular material. Rock size, composition, moisture, and void spaces between individual pieces can affect the actual weight.
This calculator uses 100 pounds per cubic foot as a starting estimate. That works out to approximately:
That is approximately 1.35 US tons per cubic yard at that assumed density. Your supplier's actual weight specification should be used when available.
How many tons of river rock do I need?
To estimate tons, first calculate the volume of river rock in cubic feet. Multiply that volume by the estimated density and divide the resulting pounds by 2,000.
Because river rock density varies, tonnage should be treated as an estimate unless you have a weight specification from your supplier.
River rock cost calculator
River rock prices vary depending on the rock type, size, supplier, location, quantity, and delivery distance.
If you know the price per ton, enter it into the calculator to estimate the material cost.
The estimated cost does not include delivery, labor, landscape fabric, edging, excavation, or other installation materials.
What depth should river rock be?
The appropriate depth depends on the type and size of river rock and what the area will be used for.
Decorative landscaping areas often use a relatively shallow layer, while projects involving larger rock or areas where deeper coverage is desired may require more material.
A 2-inch depth can be used as a starting point for many decorative applications, but it should not be treated as a universal requirement. Follow your landscape plan or supplier's recommendations when available.
River rock for landscaping
River rock is commonly used around flower beds, trees, pathways, drainage areas, borders, and other landscape features. Because the rocks are rounded and vary in size, they can create a different appearance and coverage pattern than crushed stone or pea gravel.
Before ordering material, measure the actual area and decide on the desired depth. This gives you a more useful estimate than simply estimating the number of bags or tons from the area alone.
Example river rock calculation
Suppose you want to cover a 30-foot by 15-foot landscaping area with 2 inches of river rock.
- Length: 30 feet
- Width: 15 feet
- Area: 450 square feet
- Depth: 2 inches
- Depth in feet: 0.1667 feet
- Volume: about 75 cubic feet
- Volume: about 2.78 cubic yards
If the material density is estimated at 100 lb/ft³, the weight would be approximately 7,500 pounds, or 3.75 tons.
This demonstrates why both the depth and material density matter when estimating the amount of river rock required.
Why your actual river rock requirement may be different
A river rock calculator provides an estimate rather than an exact purchasing quantity. Your actual requirement can differ because of:
- Different rock sizes
- Different rock densities
- Irregular rock shapes
- Uneven ground
- Sloped areas
- Variations in installation depth
- Settling after installation
- Measurement errors
- Material lost during installation
For larger projects, compare your calculated quantity with the coverage or weight information provided by your local supplier.
Frequently asked questions
How much river rock do I need?
The amount depends on the length, width, and desired depth of your project. Enter those measurements into the calculator to estimate cubic yards, cubic feet, and tons.
How do I calculate how much river rock I need?
Multiply the length by the width and then multiply by the desired depth in feet. Divide the result by 27 to convert cubic feet into cubic yards.
How much river rock does one yard cover?
It depends on the depth. One cubic yard theoretically covers about 162 square feet at 2 inches deep, 108 square feet at 3 inches, and 81 square feet at 4 inches.
How many yards of river rock do I need?
Calculate the volume in cubic feet and divide it by 27. The result is the estimated number of cubic yards required.
How much does a yard of river rock weigh?
The weight varies by rock type and density. At an assumed density of 100 lb/ft³, one cubic yard would weigh about 2,700 pounds, or 1.35 tons.
How deep should river rock be?
The appropriate depth depends on the rock size and application. Around 2 inches can be a useful starting point for some decorative landscaping areas, but project-specific recommendations should take priority.
How much river rock do I need for 2 inches?
At a 2-inch depth, one cubic yard theoretically covers about 162 square feet. Enter your area's dimensions into the calculator to get the amount required for your project.
Can I use this for other types of gravel?
The volume calculation can be used for other aggregate materials, but density varies between materials. Use a calculator or density value appropriate for the specific material you are buying.
How accurate is a river rock calculator?
It provides a useful estimate, but actual material requirements can vary because of rock size, density, shape, ground conditions, settling, and installation depth.