Landscape projects using rocks are tough tasks. Ordering the wrong amount can lead to delays, extra costs, or wasted materials. Updating your landscaping to incorporate decorative boulders or rock pathways requires an accurate product estimation.
If you’re wondering how much landscape rock you need, this yardage guide will be a helpful resource. Victory Greens has been helping contractors and landscapers simplify material calculations for over 30 years. Read on and learn how to get the calculation right.
Learn the Different Types of Landscaping Rocks
Not all landscape rocks serve the same purpose or provide equal coverage. River rock—with its smooth, rounded edges—ranges from small pea gravel to large cobbles. Small sizes (between 3/8 of an inch to 3/4 of an inch) are great for pathways and ground cover, while large sizes (2 inches to 6 inches) suit drainage and decorative accents. Rocks’ rounded shapes require more volume for full coverage compared to angular materials.
Lava rock is lightweight and porous. It covers more area per ton and works well for drainage, though its irregular surface may require extra rocks to accommodate for any settling.
Crushed stone and decomposed granite pack together tightly. They’re ideal for stable pathways and driveways with less material needed due to their compacting nature.
For flagstone and large, decorative rocks, coverage is typically calculated by square footage. The thickness varies based on the selected stones. Each material has unique characteristics that impact coverage and functionality, so selecting the best type for your yard is key to the project’s success.
Calculate the Area for Your Landscape Rock Project
For simple shapes, calculate square footage using basic formulas: length × width for rectangles or πr² for circles. For example, a pathway 50 feet long and 4 feet wide covers 200 square feet. Irregular shapes can be broken into smaller sections, like rectangles or triangles, to simplify calculations. Measure each section, calculate its area, and add them together for the total square footage.
For large or complex areas, use a measuring wheel to save time and increase accuracy, especially on uneven terrain. Remember to subtract the area of existing features like trees or structures. For instance, an area with 300 square feet and a tree zone of 50 square feet only needs materials for 250 square feet.
Determine the Appropriate Rock Depth
Depth requirements vary based on your project and rock type. For ground cover and decorative areas, 2 to 3 inches of depth is usually enough to provide coverage while showcasing plants and landscape features. Shallow layers work well for minimal foot traffic and aesthetic purposes. For pathways and high-traffic areas, 3 to 4 inches will provide stability and prevent shifting.
Drainage projects, like French drains or dry creek beds, need at least 6 inches of depth to handle water flow and settling effectively. In climates with freeze-thaw cycles, slightly deeper layers help prevent shifting from frost heaving. Choosing the proper depth avoids shortages, reduces costs, and ensures long-term performance.
Convert Measurements to Cubic Yards
To calculate cubic yards, first convert depth to feet. Multiply the area in square feet by the depth to get cubic feet, then divide the calculation by 27 to convert the number to cubic yards.
For example, a 200-square-foot area with 3 inches of depth requires about 1.85 cubic yards. Use the following formula:
(Length × Width × Depth in feet) ÷ 27
Use Online Calculators
Online landscape calculators simplify the estimation process by automating the math. Just input your area, depth, and material type for a cubic yard estimate. They account for material densities and coverage rates, offering more accurate results than generic calculators.
However, they can’t factor in site-specific conditions like grade variations or drainage needs. Our Victory Greens team can help refine your calculations and provide expert recommendations based on local conditions.
Account for Waste and Settling
Professional contractors understand that calculated material volumes are just a starting point, as real-world factors often demand more. It’s recommended to add 10 to 15 percent more material to account for waste, fitting, and irregular edges, with complex projects sometimes requiring up to 20 percent more.
Settling is another key consideration. Rounded materials, like river rock, may need 5 to 10 percent extra rock to account for natural settling.
Compacted materials like decomposed granite and crushed stone require even more, often needing 15 to 20 percent of additional material due to compression during installation. It’s always better to have slightly too much material than risk project delays waiting for more. Victory Greens allows for unused material storage or offers credit for unopened bags, making slight over-ordering a wise choice.
Estimate the Rock Quantity
Different landscape applications require specific material depths to guide your estimates. Rock gardens often use between 2 and 3 inches of smaller decorative rock (1/2-inch to 2-inch diameter) with large accent boulders.
For a 100-square-foot rock garden, plan for 0.75 to 1 cubic yard of base material plus focal point stones. Pathways need 3 to 4 inches of stable material like crushed stone or river rock. A 50-foot path that’s 4 feet wide requires about 2.5 cubic yards of rock.
Drainage beds require 6 inches or more of angular material that resists compaction, with one cubic yard typically covering 50 square feet, depending on drainage needs. For mulch replacement using decorative rock, it’s recommended to use between 2 and 3 inches of rock to suppress weeds and maintain a clean appearance.
Order Rocks From Victory Greens
Victory Greens stocks over 50 different types of landscape rock, from functional drainage materials to stunning decorative options. Our bulk pricing makes large projects more affordable, while our delivery service saves you time and transportation hassles.
Our delivery trucks handle 1 to 8 yards of material per load, perfect for most residential and commercial landscape projects. We’ll work with you to schedule delivery when it’s most convenient for your project timeline.
Not sure which rock type works best for your specific application? Our experienced team can recommend bulk landscaping materials based on your project requirements, budget, and aesthetic preferences. We’ve helped thousands of contractors and landscapers select the right materials for successful installations.
Victory Greens also offers Keystone blocks, Garden Wall systems, and Basalite pavers to complement your rock installations. One-stop shopping simplifies your material sourcing and often qualifies for additional bulk discounts.
Plan Your Next Landscape Rock Project
Accurate material estimation separates successful landscape professionals from those constantly dealing with shortages and delays. By understanding how to calculate the amount of landscape rock you need, you’ll order enough every time.
Our experienced team at Victory Greens stands ready to help verify your calculations and recommend the best materials for your specific projects. With over 30 years of experience serving Idaho’s landscape professionals, we understand the unique challenges you face and the materials that perform best in our local climate.
Contact Victory Greens at (208) 888-5551 to discuss your material needs, schedule delivery, and ensure your next installation goes smoothly from start to finish. Our wholesale pricing and reliable delivery service help keep your projects profitable and on schedule.