Whether you are leveling a backyard, preparing a foundation for a shed, or filling in a low spot in your landscape, knowing exactly how much fill dirt to order is crucial. Ordering too little leads to project delays and double delivery fees, while ordering too much leaves you with a massive pile of unwanted soil on your driveway.
Fill Dirt Calculator
*Truckloads based on a standard 10-yard dump truck.
Understanding the Math
Calculating fill dirt is essentially a volume calculation. Most suppliers sell dirt by the cubic yard. To find this, you need three measurements: length, width, and depth. However, the challenge usually lies in the fact that depth is measured in inches, while length and width are measured in feet.
The Basic Formula
To calculate the cubic yardage manually, use the following steps:
- Step 1: Multiply Length (ft) x Width (ft) to get the square footage.
- Step 2: Convert your Depth from inches to feet (Depth in inches / 12).
- Step 3: Multiply the Square Footage by the Depth in feet to get Cubic Feet.
- Step 4: Divide the total Cubic Feet by 27 (since there are 27 cubic feet in one cubic yard).
Factors That Affect Your Order
It is rarely a good idea to order the exact amount your calculator suggests. There are several real-world variables that can change your requirements:
1. Compaction
Fill dirt is loose when it is delivered. Once you spread it and walk on it—or use a plate compactor—it will settle. Depending on the soil type, you may lose 10% to 20% of the volume through compaction. Always add a "fudge factor" to your order to account for this.
2. Soil Type
Not all fill dirt is created equal. "Clean fill" is usually free of large rocks and debris, while "bank run" might contain more stones. If you are using screened topsoil for the top layer, remember that it compacts differently than heavy clay-based fill dirt.
3. Irregular Shapes
If your area isn't a perfect rectangle, the calculation becomes more complex. For circular areas, use the formula π x r² x depth. For irregular shapes, it is often best to break the area down into several smaller rectangles, calculate each, and add them together.
How Much Does a Truck Hold?
When you call a local quarry or landscaping supply company, they will ask how many "yards" you need. For reference:
- Small Pickup Truck: Approximately 0.5 to 1 cubic yard.
- Standard Dump Truck: Approximately 10 to 12 cubic yards.
- Large Tri-Axle Truck: Approximately 15 to 18 cubic yards.
Knowing these sizes helps you visualize the delivery and ensure you have enough space on your property for the drop-off.