Landscape Rock Calculator
Calculate how much landscape rock, gravel, or stone you need for your landscaping project. Enter the dimensions of your area, choose your rock type, and get results in cubic yards, cubic meters, tons, and bags — all with a waste factor for accuracy.
What Is a Landscape Rock Calculator?
A landscape rock calculator is a tool that helps you estimate the amount of decorative stone, gravel, or rock needed for landscaping projects. It calculates the volume, weight, and number of bags required based on the dimensions of the area and the desired depth of rock coverage.
This calculator supports four shapes — Rectangle, Square, Circle, and L-Shape — and includes multiple rock types with their respective densities. Results are provided in cubic yards, cubic meters, tons, and bags.
How Does the Landscape Rock Calculator Work?
The calculator uses the following formulas:
Area: Based on the selected shape (Rectangle: L×W, Square: s², Circle: π×r², L-Shape: (A×B)+(C×D))
Volume: Area × Depth (converted to feet or meters)
Cubic Yards: Volume (ft³) ÷ 27
Cubic Meters: Volume (m³)
Weight (Tons): Volume (ft³) × Density (lb/ft³) ÷ 2000
A waste factor (default 10%) is applied to account for spillage and uneven ground. The calculator also estimates the number of bags needed based on your selected bag size and the density of the rock type.
Why Use This Landscape Rock Calculator?
- Four Shapes: Supports rectangle, square, circle, and L-shaped areas.
- Six Rock Types: Choose from pea pebble, river rock, crushed stone, lava rock, decomposed granite, and decorative boulders.
- Unit Flexibility: Switch between imperial (feet, inches) and metric (meters, centimeters).
- Weight & Bag Estimation: Get results in tons and the number of bags needed.
- Waste Factor & Cost: Add a waste factor and estimate total material cost.
- Free & Private: No registration, no data storage.
❓ Landscape Rock Calculator FAQ
How do I calculate how much landscape rock I need?
Measure the length and width of the area, then decide how deep you want the rock layer. The calculator multiplies these to find the volume in cubic yards or cubic meters.
What is the formula for calculating rock volume?
Volume = Length × Width × Depth. Then convert to cubic yards by dividing by 27. For circular areas, use Volume = π × r² × Depth.
How many cubic feet are in a cubic yard of rock?
There are 27 cubic feet in one cubic yard.
How much does a cubic yard of landscape rock weigh?
It depends on the rock type. River rock weighs about 2,700-3,000 lbs per cubic yard, while lava rock is lighter at about 1,500-2,000 lbs per cubic yard.
What depth of rock should I use?
Common depths: 2-3 inches for decorative rock, 3-4 inches for driveways, and 4-6 inches for drainage applications.
What is the best rock for landscaping?
It depends on your project. River rock is smooth and decorative, crushed stone is angular and good for driveways, and lava rock is lightweight and good for garden beds.
How many bags of rock are in a cubic yard?
One cubic yard is about 27 cubic feet, which is approximately 14-18 bags depending on bag size and rock density.
What is a waste factor and why is it important?
The waste factor accounts for spillage and uneven ground. A typical waste factor is 5-10% to ensure you don't run short.
What is the density of different rock types?
Pea pebble: ~100 lb/ft³, River rock: ~110 lb/ft³, Crushed stone: ~120 lb/ft³, Lava rock: ~60 lb/ft³, Decomposed granite: ~100 lb/ft³, Boulders: ~120 lb/ft³.
How do I convert cubic yards to tons of rock?
Multiply cubic yards by the density in lb/ft³, then divide by 2000. The calculator does this for you.
How do I calculate rock for an irregular shape?
Divide the irregular shape into regular shapes (rectangles, squares, etc.), calculate each area, and add them together.
Should I buy bagged or bulk landscape rock?
Buy bags for small jobs (under 0.25 cubic yards). Choose bulk delivery for larger projects (1+ cubic yards) to save money.
How much rock do I need for a 10×10 area?
A 10×10 area at 3 inches deep needs about 0.93 cubic yards of rock.
How much rock do I need for a circular garden bed?
Use the Circle shape mode. Enter the radius of your circular bed and the desired depth.
What is the difference between river rock and pea gravel?
River rock is smooth, rounded, and larger (1-3 inches). Pea gravel is smaller, smoother, and typically 1/4-1/2 inch in size.
How do I prevent weeds from growing through landscape rock?
Install a weed barrier fabric underneath the rock layer. This prevents weeds from growing up through the rock while still allowing water to drain.
Can I use this calculator for decorative boulders?
Yes. Select the "Decorative Boulders (large)" rock type. For boulders, you'll typically need to calculate by weight rather than volume.
How do I maintain landscape rock?
Rake periodically to keep the rock layer even. Remove leaves and debris to prevent weed growth. Occasionally wash the rocks to keep them looking fresh.