A river rock calculator helps you determine the right amount of material by multiplying your project's length, width, and depth in feet, then dividing by 27 for cubic yards.
Expect to pay $200 to $500 for a 100-square-foot river rock installation, with costs varying based on your project size and rock type.
Measure rectangular areas by multiplying length times width times depth, or estimate curved spaces using the longest length times average width for your coverage needs.
Hiring a local landscaping professional removes the physical demands of installation and ensures your river rock arrangement looks polished and stays in place for years.
How much river rock do I need? Let’s dive in. Whether you’re using river rock for a pathway, garden bed, or water feature, buying the right amount is key to the success of your landscaping project. The amount you need depends on the size of your space. Here’s how to calculate the right amount of river rock for your project.
The amount of river rock you need will depend largely on the size of your landscaping project. In the table below, you can see approximately how much river rock to buy for different project sizes.
River rock installations typically range from 2 to 4 inches in depth but can vary significantly in length and width. To find the square footage of your project, simply multiply the length and width of the space.
Heads up: Landscaping and garden supply companies sell river rock in a few different ways, including by volume (in cubic yards) or weight (in tons). For the purpose of this river rock calculator, we’ll use cubic yards.
| Project Size | Cubic Yards of River Rock Required | Average Cost |
|---|---|---|
| 10 sq. ft. | 0.06–0.12 | $150–$300 |
| 25 sq. ft. | 0.15–0.3 | $150–$300 |
| 50 sq. ft. | 0.3–0.6 | $150–$300 |
| 100 sq. ft. | 0.7–1.3 | $200–$500 |
| 500 sq. ft. | 3–6 | $400–$1,800 |
To figure out how much river rock you should order, you’ll need to know the length, width, and depth of your project area. When you multiply these dimensions, you’ll get the size of your project in cubic feet. Then, to convert it to cubic yards, you’ll divide by 27.
Here’s how the formula works:
Total River Rock Required (in cubic yards) = (Length (in feet) x Width (in feet) x Depth (in feet)) / 27
For example, let’s say you’re planning to install river rock in a space that’s 5 feet wide, 10 feet long, and 3 inches deep. This means you’ll need 12.5 cubic feet—or 0.46 cubic yards—of rocks.
Before you can calculate how much river rock to order, you’ll need to take a few measurements and do some basic math. Here are the steps to follow, depending on the shape of your space:
If you’re filling in a rectangular area (like a driveway or pathway) with river rock, here’s how to calculate how much rock you need:
Measure the length and width of the space.
Choose a depth for your river rock installation (typically, this should be between 2 and 4 inches).
Convert all three figures into feet.
Multiply them together to get the volume of river rock in cubic feet.
Divide the result by 27 to convert from cubic feet into cubic yards and get the total amount of river rock you need.
To find the square footage of a circular area, follow these steps:
Measure the diameter of the circle and divide it in half to find the radius.
Square the radius by multiplying it by itself.
Multiply the squared radius by pi (π = 3.14159265) to get the square footage of the area.
Multiply the area’s square footage by the depth of your river rock (in feet) to get the volume of river rock in cubic feet.
Divide the result by 27 to convert from cubic feet into cubic yards and get the total amount of river rock you need.
For curved areas (for example, around a pond or along a garden bed), it’s easier to estimate how much river rock you should order rather than trying to get an exact number. Here’s how to do that:
Measure the longest length of the space.
Estimate the area’s average width.
Multiply the length, width, and depth of your river rock (all in feet) to get the volume in cubic feet.
Divide the result by 27 to convert from cubic feet into cubic yards and get the total amount of river rock you need.
Installing river rock is a physically demanding job, and arranging them in an aesthetically pleasing way is often harder than it looks. Instead of attempting this type of project yourself, it’s better to work with a local landscaper who can plan and manage the installation of river rock at your home.
If you’ve never hired a landscape designer before, here are a few tips to keep in mind:
Know what services you want and have a budget in mind before reaching out.
Interview multiple candidates.
Before hiring a landscaping contractor, check their qualifications, references, and online reviews.
Get all estimates and the final contract in writing.
I recently moved to another state and chose United Trust Van Lines after comparing several companies. Their team was punctual, professional, and extremely careful with my belongings. I was especially impressed with how they handled my home office setup and fragile items. Everything arrived on...
United Trust Van Lines, LLCThis company does it right. Firstly, I want to say that Landan was a joy to work with. He was so kind, transparent, and had everything under control. His entire team showed up ready to work and they were all very respectful of the fact that we were in an office space. A little backstory – we...
Krumlauf FloorsD1 Roofing delivers outstanding service from beginning to end, backed by a strong warranty and expert teams. I highly recommend them for their excellence in meeting and surpassing expectations with unmatched communication. Choosing D1 Roofing was flawless decision
Division 1 Roofing LLCI'm a repeat customer of All Star Paving & Sealing and I appreciate the service that all start paving has done for me in the past. I just recently had them out for an estimate and things couldn't have gone better. The staff that they send out to do the estimates are very knowledgeable. The...
All Star Paving and SealingSupreme Brick & Chimney did an excellent job restoring the brick and mortar joints on my home. Their team was professional, knowledgeable, and completed the work on time. I highly recommend them and will hire them again in the future! Thanks!
Supreme brick & chimneyOn time, clean and finished fast. Windows seem sturdy and the finish is good. Caulking was done with no smudges. Would recommend.
Window Depot USA of Central OhioThey are very reliable and available. They the drains all the time
The WaterworksMary cleaning service does an amazing job cleaning my home. They go over and beyond the cleaning services that I have had in the past. They are very punctual and thorough with cleaning my home, I’m extremely happy with the service they provide and I highly recommend them.
We had a 20+ year old landscape lighting system that needed replacement. Midwest Lightscapes worked with us to design a much improved lighting system, lighting the exterior of the house and the back yard. Installation of the 45 light system took one and one-half days, and went very smoothly....
Midwest LightscapesManuel Calvillo is the best option in the area for roofing and you won't be disappointed.
From average costs to expert advice, get all the answers you need to get your job done.
From your flower beds to your walkway, river rocks make a classic addition to your landscape. Learn about the cost to install river rock to set a proper budget.
What size river rock is best for landscaping? Learn all about choosing landscaping rocks for gardens, water features, walkways, and more.
Find out the best types of landscaping rocks for your home’s next outdoor project, from solving drainage problems to installing retaining walls and terraces.
What are the best rocks for French drains? Learn which rocks top the list and which ones to avoid using for a French drain.
Save yourself time, energy, and a whole lot of water with these low-maintenance landscaping ideas. Keep your lawn looking stylish with far less work.
Landscaping rocks are used for a variety of landscaping designs. Learn how to keep landscape rocks in place to keep your yard looking great.
