Updated on September 5th, 2025

River Rock Calculator

Created By Jehan Wadia

Select Area Shape
Rectangle
Circle
Triangle
Custom/Multiple
tons/cubic yard
Depth Coverage/Ton
1"250 sq ft
2"125 sq ft
3"83 sq ft
4"63 sq ft
%
%
$
$
$
$

Introduction

The River Rock Calculator helps you figure out how much river rock you need for your project. River rock is a smooth stone used for gardens, paths, and driveways. It comes in different sizes and adds beauty to outdoor spaces.

This tool makes it easy to plan your project. Just pick your area shape, enter the size, and choose how deep you want the rocks. The calculator tells you how many tons or cubic yards to buy. It also shows the total cost based on current prices. For similar projects, you might also need our Pea Gravel Calculator for smaller stone sizes or our Concrete Calculator if you're creating a solid base.

Whether you're making a garden bed, building a walkway, or covering a large area, this calculator saves you time and money. It adds extra amounts for waste and settling, so you don't run short. You can even calculate multiple areas at once for bigger projects.

How to use our River Rock Calculator

Enter your project area size and depth to find out how much river rock you need. The calculator will show you the amount in cubic yards, tons, and total cost.

Select Area Shape: Pick the shape that matches your project area - rectangle, circle, triangle, or custom for multiple zones.

Length: Enter how long your area is in feet, meters, or inches (shows for rectangle shapes).

Width: Enter how wide your area is in feet, meters, or inches (shows for rectangle shapes).

Radius: Enter the distance from the center to the edge for circular areas (shows for circle shapes).

Base: Enter the bottom edge length for triangle areas (shows for triangle shapes).

Height: Enter the vertical height for triangle areas (shows for triangle shapes).

Depth: Enter how thick you want the river rock layer to be, usually 2-4 inches for most projects.

River Rock Size: Choose the size of rock you want, from small pea gravel to large 3-5 inch rocks.

Material Density: Set the weight of rock per cubic yard - most river rock is about 1.3 tons per cubic yard.

Waste Factor: Add extra percentage for spillage and uneven ground - usually 10% is enough.

Compression Factor: Add extra for settling over time - typically 15% for river rock.

Price per Ton: Enter what your supplier charges for each ton of river rock.

Price per Cubic Yard: Enter the cost if buying by volume instead of weight.

Price per Bag: Enter the cost for bagged river rock from stores.

Delivery Fee: Add any delivery charges from your supplier to get the full project cost.

What is River Rock?

River rock is a type of smooth stone that comes from riverbeds and beaches. These rocks get their round shape from water moving over them for many years. River rocks come in different sizes, from tiny pea gravel that is less than half an inch wide to large stones that are 5 inches across. People use river rock for many outdoor projects because it looks nice and lasts a long time.

Common Uses for River Rock

River rock works great for many home and garden projects. You can use it to make pathways and walkways that drain water well. It helps stop weeds when you put it in flower beds. Many people use river rock around trees and plants to keep the soil moist. It also works well for drainage areas where water needs to flow away from your house. Driveways can use larger river rocks for a strong surface that lets water through. If you're planning a driveway project, check our Asphalt Calculator to compare material options.

How Much River Rock Do


Frequently Asked Questions

How many bags of river rock do I need for 100 square feet?

For 100 square feet at 2 inches deep, you need about 33 bags of river rock. Each bag covers about 3 square feet at 2 inches deep. For 3 inches deep, you need 50 bags. Always buy a few extra bags for uneven spots.

What size river rock is best for drainage?

Use 1-2 inch river rock for most drainage projects. This size lets water flow through easily but won't wash away in heavy rain. For French drains, 3/4 inch to 1.5 inch rocks work best. Bigger rocks handle more water flow.

How deep should river rock be for landscaping?

Put river rock 2-3 inches deep for flower beds and gardens. Use 3-4 inches for walkways to prevent seeing the ground underneath. Driveways need 4-6 inches of river rock to handle car weight. Add landscape fabric under the rocks to stop weeds.

How much does a cubic yard of river rock weigh?

A cubic yard of river rock weighs about 2,600 pounds or 1.3 tons. Smaller rocks like pea gravel weigh less at about 2,500 pounds per yard. Larger 3-5 inch rocks can weigh up to 3,000 pounds per yard when dry.

Can I put river rock directly on soil?

You can put river rock on soil, but it's better to use landscape fabric first. The fabric stops weeds from growing through the rocks. It also keeps rocks from sinking into soft soil. Without fabric, you'll need to pull weeds and add more rocks over time.

How much area does 1 ton of river rock cover?

One ton of river rock covers about 100 square feet at 2 inches deep. At 3 inches deep, it covers 75 square feet. At 4 inches deep, it covers 50 square feet. Smaller rocks spread further than larger ones.

What's cheaper - buying river rock by the ton or cubic yard?

Buying by the ton is usually cheaper for large amounts. Bulk prices range from $30-65 per ton or $40-85 per cubic yard. Bagged river rock costs more at $5-10 per bag. For projects over 5 cubic yards, always buy in bulk to save money.

How do I keep river rocks from moving?

Use edging like metal, plastic, or stone borders to keep rocks in place. Pack rocks tightly and use the right depth - at least 2 inches. For slopes, use larger rocks or add a stabilizer grid underneath. Avoid using river rock on steep hills.


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