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Fill Dirt Calculator

Calculate fill dirt volume, weight, truckloads, and project cost for grading, backfilling, landscaping, and site preparation. Supports multiple project shapes and Metric or Imperial units.

CalculatorHow to CalculateFormulas & ExamplesFAQs

Select a shape, enter dimensions, set density and truck capacity, then calculate.

Dimensions

10%

Density & Logistics

lb/ft³

Material Cost Estimates (Optional)

Calculation Results

Awaiting Calculations

Fill in the shapes, dimensions, fill depth, density parameters, and click Calculate to view estimates.

Formula Details

Project Area Formula
Area = L × W (Rect) | S² (Square) | πD²/4 (Circle) | 0.5 × B × H (Triangle) | L × W_top (Trench)

Computes physical surface area of the project zone based on the layout shape.

Variables Explained
  • L / W
    Length / Width:Horizontal bounds for rectangular layouts.
  • S
    Side Length:Horizontal bounds for square layouts.
  • D
    Diameter:Diameter dimension across circular fills.
  • B / H
    Base / Height:Triangular run dimensions.
  • W_top
    Trench Top Width:Width of trench opening at ground level.
Fill Dirt Volume Formula
Volume = Area × Depth (Shapes) | Length × ((W_top + W_bottom) / 2) × Depth (Trench)

Finds the raw volume of fill dirt needed. Trench volume utilizes a trapezoidal cross-sectional area to support sloping walls.

Variables Explained
  • Area
    Surface Area:Surface footprint of the shape.
  • Depth
    Fill Depth:Vertical thickness of the soil layer needed.
  • W_bottom
    Trench Bottom Width:Width of trench bed at the bottom.
Volume with Compaction & Waste
Total Volume = Volume × (1 + Waste Percentage / 100)

Adjusts calculated soil volume to include waste allowance and compaction shrinkage (typically 10% to 15% is added).

Variables Explained
  • Waste
    Compaction / Waste Factor:Allowance percentage added for loose soil settling and site wastage.
Weight & Truckloads Formulas
Weight = Total Volume × Density | Truckloads = Total Volume / Truck Capacity

Estimates the weight of the dirt and determines the total number of truck deliveries required based on vehicle capacity.

Variables Explained
  • Density
    Soil density:Density of soil (default is 100 lb/ft³ or 1600 kg/m³).
  • Capacity
    Truck Capacity:Carrying volume of the haul truck (e.g. 5, 10, 15, or 20 cubic yards/meters).

Calculation Example

Worked Example
Scenario

Estimate fill dirt, weight, and delivery truckloads to level a backyard garden measuring 30 feet by 20 feet to a depth of 4 inches, using a 10% waste/compaction allowance and a standard 5 cubic yard truck preset.

Calculation Steps
  1. 1.Compute surface area of the rectangular yard.
    Area = 30 ft × 20 ft = 600 sq ft
  2. 2.Convert depth to feet and calculate net volume.
    Depth = 4 in = 4/12 ft = 0.333 ft | Net Volume = 600 sq ft × 0.333 ft = 200 cu ft
  3. 3.Apply 10% compaction & waste factor.
    Total Volume = 200 cu ft × 1.10 = 220 cu ft
  4. 4.Convert cubic feet volume to cubic yards.
    Volume in Yards = 220 cu ft / 27 = 8.15 cu yd
  5. 5.Calculate total weight using the default density of 100 lbs/ft³.
    Weight = 220 cu ft × 100 lbs/ft³ = 22,000 lbs | In US Tons = 22,000 lbs / 2,000 = 11 US Tons
  6. 6.Determine truckloads needed (5 cubic yard truck capacity).
    Truckloads = 8.15 cu yd / 5 cu yd = 1.63 Trucks | Rounded up = 2 Truckloads
Final Quantity Needed8.15 Cubic Yards (~11 Tons) & 2 Truckloads
Worked Example
Scenario

Calculate soil backfill requirements for a utility trench 50 feet long, with a top opening width of 3 feet, a bottom width of 2 feet, and depth of 4 feet. Use a 15% compaction buffer, default soil density, and a 10 cubic yard truck.

Calculation Steps
  1. 1.Compute trapezoidal cross-sectional area of the trench.
    Cross Section Area = ((3 ft + 2 ft) / 2) × 4 ft = 10 sq ft
  2. 2.Calculate net trench volume by multiplying by length.
    Net Volume = 50 ft × 10 sq ft = 500 cu ft
  3. 3.Apply 15% compaction and waste allowance.
    Total Volume = 500 cu ft × 1.15 = 575 cu ft
  4. 4.Convert volume to cubic yards.
    Volume in Yards = 575 cu ft / 27 = 21.30 cu yd
  5. 5.Estimate weight (95 lbs/ft³ density custom assumption).
    Weight = 575 cu ft × 95 lbs/ft³ = 54,625 lbs | In US Tons = 54,625 lbs / 2,000 = 27.31 US Tons
  6. 6.Determine truckloads needed (10 cubic yard truck capacity).
    Truckloads = 21.30 cu yd / 10 cu yd = 2.13 Trucks | Rounded up = 3 Truckloads
Final Quantity Needed21.30 Cubic Yards (~27.3 Tons) & 3 Truckloads
Worked Example
Scenario

Calculate metric quantities for a circular landscaping fill bed 8 meters in diameter, with a target soil depth of 15 cm. Use a 10% compaction factor, default density of 1600 kg/m³, and a 4 cubic meter capacity truck.

Calculation Steps
  1. 1.Compute surface area of the circular bed.
    Area = π × (8 m)² / 4 = 50.27 sq m
  2. 2.Convert depth to meters and calculate net volume.
    Depth = 15 cm = 0.15 m | Net Volume = 50.27 sq m × 0.15 m = 7.54 cu m
  3. 3.Apply 10% compaction & waste factor.
    Total Volume = 7.54 cu m × 1.10 = 8.29 cu m
  4. 4.Calculate total weight using the default density of 1600 kg/m³.
    Weight = 8.29 cu m × 1600 kg/m³ = 13,264 kg | In Metric Tons = 13.26 Metric Tons
  5. 5.Determine truckloads needed (4 cubic meter truck capacity).
    Truckloads = 8.29 cu m / 4 cu m = 2.07 Trucks | Rounded up = 3 Truckloads
Final Quantity Needed8.29 Cubic Meters (~13.3 Metric Tons) & 3 Truckloads

How to Use

Follow these simple steps to estimate the surface area, fill dirt volume, weight, and delivery truckloads for your grading or excavation project:

  1. Choose Project Shape: Select the shape of your fill zone (Rectangle, Square, Circle, Triangle, or Trench).
  2. Toggle Unit System: Select Imperial (ft/in/yd) or Metric (m/cm/mm) at the top right of the calculator.
  3. Enter Dimensions: Fill in the required length, width, or diameter fields, along with the average fill depth.
  4. Set Compaction & Waste Allowance: Drag the slider (default is 10%) to compensate for soil compaction and material loss during placement.
  5. Adjust Density & Logistics: Use the default soil density, or check "Custom" to specify your material's density. Choose a truck capacity preset or define a custom haul volume.
  6. Add Optional Costs: Input a unit price and select a currency/basis to get a cost estimate.
  7. Click Calculate: Click the Calculate button to process inputs and display area, volume, weight, truckloads, and cost estimates.

Frequently Asked Questions

What is fill dirt?
Fill dirt is subsoil retrieved beneath the top layer of earth. It lacks organic matter, meaning it does not break down or decompose over time. Because it resists volume changes and settling, it provides a stable foundation for grading, leveling, filling trenches, backfilling foundations, and overall landscaping or construction support.
How is fill dirt volume calculated?
Volume is calculated by multiplying the surface area of your project shape by the depth of fill required. For simple rectangular shapes, multiply Length × Width × Depth. For a trench, average the top and bottom widths, then multiply by the length and depth. Finally, add a waste/compaction buffer to determine the total cubic yards or cubic meters needed.
How is fill dirt weight estimated?
We estimate fill dirt weight by multiplying the total volume (including compaction allowance) by the material's bulk density. Standard loose dry fill dirt has a density of approximately 90 to 110 lbs/ft³ (1,440 to 1,760 kg/m³). In our calculator, we use 100 lbs/ft³ (1,600 kg/m³) as the default density, but you can check 'Custom' to enter a specific density provided by your supplier.
How many truckloads of fill dirt will I need?
The number of truckloads is calculated by dividing your total required volume by the carrying capacity of the truck. Standard dump trucks hold between 5 to 20 cubic yards (approx. 3.8 to 15.3 cubic meters). The calculator will show you the exact decimal truckloads needed, and round up to the nearest whole truckload to represent full deliveries.
Can I enter a custom density?
Yes. By checking the 'Custom' checkbox next to the density input, you can type a custom soil density in lb/ft³ (imperial) or kg/m³ (metric). The calculator will automatically convert these values if you toggle between the Metric and Imperial unit systems.
Should I include extra material for compaction and waste?
Yes, this is highly recommended. Soil settles and compacts when rolled, stamped, or walked on, decreasing its initial volume. Additionally, minor losses occur during transport and shoveling. Adding a 10% to 15% allowance ensures you have enough material to achieve your final graded height.

Need more material estimations?

Explore our Aggregate & Gravel Calculator, Excavation volume model, and Topsoil calculator to plan complete excavation, grading, and material layouts.

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Disclaimer

Calculations are estimates based on the values you enter and standard engineering formulas. Results are intended for planning and estimation only. Always verify critical measurements, specifications, and local building requirements before purchasing materials or beginning construction.