Total Weight: '+totalWeight.toFixed(2)+' Tons';if(document.getElementById('steps').checked){var stepsHTML='Step 1: Calculate Square Footage
'+shapeStr+'
Step 2: Calculate Cubic Feet
Volume = Area x (Depth / 12)
Volume = '+areaSqFt.toFixed(2)+' x ('+v3+' / 12) = '+volumeCuFt.toFixed(2)+' cu ft
Step 3: Convert to Cubic Yards
Yards = cu ft / 27
Yards = '+volumeCuFt.toFixed(2)+' / 27 = '+volumeCuYd.toFixed(2)+' cu yd
Step 4: Calculate Weight
Weight = Volume x Density
Weight = '+volumeCuYd.toFixed(2)+' x '+density+' = '+totalWeight.toFixed(2)+' tons';document.getElementById('stepDetails').innerHTML=stepsHTML;document.getElementById('stepDetails').style.display='block';}else{document.getElementById('stepDetails').style.display='none';}}
Calculator Use
Our rock calculator is a professional-grade tool designed for homeowners, landscapers, and contractors to accurately estimate the quantity of rock, gravel, or stone needed for any project. Whether you are building a new gravel driveway, filling a garden bed with decorative river rock, or laying a base for a patio, knowing exactly how much material to order is crucial for budgeting and logistics.
To use the rock calculator, simply choose your project shape (rectangle or circle), enter the dimensions in feet, specify your desired coverage depth in inches, and provide the density of the rock type you are using. The tool will instantly provide the total volume in cubic yards and the total weight in tons.
- Length / Diameter
- The linear distance of the area. For circular pits or beds, use the diameter (the distance from one side to the other through the center).
- Width
- The side-to-side distance for rectangular or square areas.
- Depth
- How thick you want the rock layer to be. Standard landscape coverage is usually 2 to 4 inches.
- Density
- The weight of the rock per unit of volume. Most landscape rocks average about 1.35 tons per cubic yard.
How It Works
The rock calculator uses standard geometric formulas to find volume and then applies a density multiplier to find weight. The process follows these mathematical steps:
Volume (Cubic Yards) = [Area (sq ft) × (Depth (in) / 12)] / 27
- Area: Calculated as Length × Width for rectangles, or π × (Diameter/2)² for circles.
- Depth Conversion: Depth is divided by 12 to convert inches into feet, ensuring all units are consistent.
- Cubic Yard Conversion: Since there are 27 cubic feet in one cubic yard, we divide the total cubic feet by 27.
- Weight Calculation: Weight = Volume (yd³) × Density (Tons/yd³).
Common Rock Densities
Different types of stone have different weights. If you aren't sure what density to use in the rock calculator, refer to these common estimates:
| Material Type | Density (Tons per Yard) |
|---|---|
| Crushed Limestone | 1.4 – 1.6 |
| River Rock / Pea Gravel | 1.2 – 1.3 |
| Lava Rock | 0.6 – 0.8 |
| Sandstone | 1.1 – 1.2 |
| Decomposed Granite | 1.3 – 1.5 |
Calculation Example
Example: You want to cover a rectangular flower bed that is 20 feet long and 5 feet wide with 3 inches of river rock (density 1.3 tons/yd³).
Step-by-step solution:
- Area: 20 ft × 5 ft = 100 sq ft
- Volume in Cu Ft: 100 sq ft × (3 in / 12) = 100 × 0.25 = 25 cu ft
- Volume in Yards: 25 / 27 = 0.925 cubic yards
- Total Weight: 0.925 yd³ × 1.3 tons/yd³ = 1.20 tons
- Result: You should order approximately 1 cubic yard (to be safe) or 1.2 tons of rock.
Common Questions
How deep should landscape rock be?
For most decorative applications, a depth of 2 to 3 inches is sufficient. If you are using larger rocks (over 1 inch in diameter), you may need a depth of 4 inches to ensure the ground underneath is completely covered and hidden from view.
Does the rock calculator account for compaction?
This rock calculator provides the "loose" volume. If you are compacting the rock (like for a driveway sub-base), you should add about 15-20% to your final total to account for the material settling and packing down.
Why calculate by weight instead of volume?
Many quarries and landscape supply yards sell rock by the ton rather than by the cubic yard. Because different rocks have different weights (e.g., lava rock is much lighter than granite), calculating the tonnage ensures you get the right amount and are billed correctly for the specific material you choose.