Fill Dirt / Excavation Calculator
Calculate the volume of dirt you need to bring in for filling or haul away for excavation, with estimates for weight, truck trips, and material cost.
What is Fill Dirt / Excavation?
A fill dirt and excavation calculator computes the volume of earth material involved in grading, backfilling, trenching, or excavation projects. Whether you are filling a low spot in your yard, backfilling around a foundation, building up a pad for a shed, or digging out for a pool, knowing the precise volume in cubic yards is essential for ordering materials and estimating costs. Fill dirt is subsoil that has been excavated from one location and transported to another. Unlike topsoil, it contains minimal organic matter and is valued for its stability and compaction properties. It is used for raising grade levels, backfilling retaining walls, filling holes and depressions, creating building pads, and establishing proper drainage slopes around structures. The basic calculation multiplies length by width by depth to get cubic feet, then divides by 27 to convert to cubic yards (the standard unit for bulk earth material ordering). The shape factor allows you to adjust for irregular areas: a perfect rectangle uses 1.0, while an oval or irregular shape uses approximately 0.8 (or pi/4 = 0.785 for ellipses). Weight conversion is important for transport logistics. Fill dirt typically weighs 1.0 to 1.3 tons per cubic yard depending on moisture content and composition. This calculator uses 1.1 tons per cubic yard as a standard average. Clay-heavy soils weigh more; sandy soils weigh less. Wet soil can weigh 20-30% more than dry soil. Standard dump trucks carry 10-14 cubic yards per load depending on the truck size. This calculator uses 10 cubic yards per truck as a conservative estimate for a standard tandem-axle dump truck. Knowing the number of truckloads helps you plan delivery logistics, estimate how long the project will take, and budget for per-load delivery charges. Material cost for fill dirt varies significantly by region and quality. Clean fill (free of debris and contaminants) runs $10-20 per cubic yard in most areas. Screened fill or structural fill costs more. In some cases, you can get free fill dirt from nearby construction sites that need to dispose of excavated material. The calculator uses $15 per cubic yard as a baseline estimate for budgeting purposes.
How to Calculate
- Measure the length and width of your fill or excavation area in feet
- Determine the average depth in feet (for sloped areas, use the average of the deepest and shallowest points)
- Set the shape factor: use 1.0 for rectangular areas, 0.8 for oval or irregular shapes, or any value between 0.5 and 1.0 for other shapes
- Review the results showing volume in cubic yards, estimated weight in tons, number of standard truckloads, and approximate material cost
Formula
Volume (cubic feet) = length (ft) x width (ft) x depth (ft) x shape_factor Cubic yards = cubic_feet / 27 Tons = cubic_yards x 1.1 (average weight of fill dirt per cubic yard) Truckloads = ceiling(cubic_yards / 10) (standard 10-yard dump truck) Estimated cost = cubic_yards x $15 per yard The shape factor reduces the rectangular volume to approximate irregular areas: 1.0 = full rectangle, 0.8 = oval/irregular, 0.5 = triangular.
Example Calculation
Filling a 20 ft x 15 ft rectangular area to a depth of 2 feet: - Volume = 20 x 15 x 2 x 1.0 = 600 cubic feet - Cubic yards = 600 / 27 = 22.22 cubic yards - Weight = 22.22 x 1.1 = 24.44 tons - Truckloads = ceil(22.22 / 10) = 3 truckloads - Estimated cost = 22.22 x $15 = $333.33 For the same area with an irregular shape (factor 0.8): - Volume = 20 x 15 x 2 x 0.8 = 480 cubic feet - Cubic yards = 480 / 27 = 17.78 cubic yards - Truckloads = ceil(17.78 / 10) = 2 truckloads - Estimated cost = 17.78 x $15 = $266.67
Frequently Asked Questions
What is the difference between fill dirt, topsoil, and clean fill?
Fill dirt is subsoil with no organic content, ideal for structural filling and grading. Topsoil is the nutrient-rich upper layer with organic matter, used for gardens and lawns. Clean fill is fill dirt certified free of contaminants, rocks, and debris, required for regulated projects.
How much does a cubic yard of dirt weigh?
Dry fill dirt weighs approximately 2,000-2,200 pounds (1.0-1.1 tons) per cubic yard. Wet or clay-heavy soil can weigh 2,400-2,700 pounds per cubic yard. Sandy soil is lighter at 1,800-2,000 pounds per cubic yard.
Should I order extra fill dirt to account for compaction?
Yes. Loose fill dirt compacts by approximately 20-30% when properly tamped or when it settles naturally over time. If you need 10 cubic yards in place after compaction, order 12-13 cubic yards to account for this reduction.
Can I get free fill dirt?
Often yes. Construction sites, road projects, and excavation contractors frequently need to dispose of clean fill dirt. Check local classifieds, community boards, or ask nearby contractors. You may need to arrange your own hauling, but the material itself is often free.
How do I calculate for a sloped area?
Measure the depth at the deepest point and the shallowest point, then use the average as your depth input. For example, if one end is 3 feet deep and the other is 1 foot deep, use 2 feet as your depth. This gives a close approximation of the wedge-shaped volume.
How many dump truck loads should I expect?
A standard tandem-axle dump truck carries 10-14 cubic yards. A single-axle truck carries 5-8 cubic yards. A transfer truck (truck plus trailer) carries 20-26 cubic yards. This calculator uses 10 cubic yards as a conservative per-load estimate that works for most residential deliveries.