The Complete Guide to Calculating Gravel for Your Project
Whether you are building a new driveway, laying a patio, or creating a drainage field, ordering the right amount of material is the first and most critical step. Order too little, and you pay for a second delivery fee. Order too much, and you have a pile of rocks killing your grass. Our advanced Gravel Calculator is designed for homeowners and contractors in the United States to precisely estimate the tons or cubic yards needed for any project.
How to Use the Gravel Calculator
We have made the math simple. Just follow these steps:
1. Determine the Shape
- Rectangle: Best for driveways, walkways, and parking pads. You will need Length and Width in feet.
- Circle: Best for fire pit areas, round patios, or tree rings. You will need the Diameter (width across the center) in feet.
2. Measure the Depth
This is how thick the layer of stone will be. Input this in Inches.
Common Depths:
- 2 Inches: Decorative landscaping or refreshing an existing driveway.
- 3-4 Inches: Standard new driveway or walkway.
- 6+ Inches: Heavy-duty foundation or base for pavers.
3. Select Your Material
Not all rocks weigh the same! A truckload of Mulch weighs significantly less than a truckload of Granite. Select the specific material from the dropdown to adjust the Density Factor (Tons per Cubic Yard).
Understanding Units: Yards vs. Tons
In the US, landscape materials are sold in two main ways:
- By Volume (Cubic Yards): Mulch, soil, and sometimes lightweight gravel are sold by the "scoop" or yard. One cubic yard is a volume of 3ft x 3ft x 3ft.
- By Weight (Tons): Most gravel, crushed stone, and sand are sold by the ton at quarries. This is because they are weighed on a scale as the truck leaves.
Our calculator automatically converts the Volume (Yards) into Weight (Tons) based on the material density.
Common Gravel Types and Uses
Pea Gravel
Small, round, smooth stones (about 3/8"). Great for walkways, playgrounds, and drainage. Not recommended for driveways as it rolls and doesn't compact well.
Crushed Stone #57
The gold standard for driveways and drainage. These angular stones lock together, creating a stable surface. Size is roughly 3/4" to 1".
Quarry Process / Crusher Run / QP
A mix of stone dust and 3/4" stone. When compacted, the dust fills the voids, creating a cement-hard surface. Ideal for driveway bases and paver foundations.
River Rock
Smooth, rounded stones used primarily for decoration and dry creek beds. They are heavy and expensive compared to crushed stone.
The Math: How It's Calculated
If you want to double-check the math manually, here are the formulas:
Step 1: Calculate Volume in Cubic Feet
For a Rectangle:
Volume = Length (ft) × Width (ft) × (Depth (in) / 12)
For a Circle:
Radius = Diameter / 2
Area = π × Radius²
Volume = Area × (Depth (in) / 12)
Step 2: Convert to Cubic Yards
There are 27 cubic feet in 1 cubic yard.
Cubic Yards = Cubic Feet / 27
Step 3: Convert to Tons
Multiply the Cubic Yards by the Material Density (Tons/Yard).
Standard Gravel Density: ~1.4 Tons per Cubic Yard.
Total Tons = Cubic Yards × 1.4
Cost Estimation
Gravel prices vary wildly by region in the US.
Average Cost: $15 - $50 per ton for standard crushed stone.
Delivery Fee: Expect to pay $50 - $150 per truckload for delivery.
Our calculator allows you to input a "Price per Ton" to estimate the material cost (excluding delivery).
Bag vs. Bulk: Which Should You Buy?
Bags: Sold at Home Depot/Lowe's. Usually 0.5 cubic feet or 50lbs. Expensive per pound but convenient for tiny projects (e.g., a single flower bed).
Bulk: Delivered by a dump truck. Significantly cheaper for anything over 1 cubic yard. If our calculator says you need more than 0.5 yards, buy bulk.
Frequently Asked Questions (FAQ)
How deep should a gravel driveway be?
For a new driveway on bare dirt, you need at least 3 layers: larger stone at the bottom, mid-size in the middle, and top dressing. The total depth should be 8-12 inches. For "top dressing" an existing driveway, 2-3 inches is sufficient.
How much does a cubic yard of gravel cover?
At a depth of 2 inches, one cubic yard covers approximately 160 square feet (a 10x16 area).
What is the difference between #57 stone and #67 stone?
They are very similar, but #67 stone is slightly smaller than #57. #57 is the most common choice for residential driveways.
Will the gravel sink?
Yes. Over time, gravel gets pushed into the soil, especially in wet conditions. To prevent this, always lay down a Geotextile Landscape Fabric before spreading your stone. It keeps the rock separate from the mud.