Fill Dirt Calculator
Estimate the volume and weight of fill dirt needed for grading, filling holes, or building up foundations.
Calculation Results
Total cubic yards of fill dirt required (includes compaction buffer).
The estimated weight of dry fill dirt in short tons.
How This Calculator Works
To calculate fill dirt requirements:
- Enter the length and width of the trench, hole, or slope area to fill.
- Specify the depth of the fill layer in inches or feet.
- Modify the dry soil density if you know the specific type of earth (default is 95 lbs/cu ft).
- Enter a soil settling allowance (compaction increases soil needs).
Formula & Calculations
Fill dirt calculations determine physical volume and total shipping weight:
Volume (Cubic Feet) = Length × Width × Depth
We scale the volume using the soil compaction factor (typically 10% to 20% to account for backfill settling):
Compacted Volume = Volume × (1 + Compaction / 100)
Weight is calculated by multiplying volume by the soil density (dry clay/soil is approx 90-100 lbs/cu ft):
Weight (lbs) = Compacted Volume (cu ft) × Soil Density (lbs/cu ft)
Step-by-Step Calculation Examples
Trench Backfill (30ft x 10ft x 12in depth)
Estimating yards and tons of standard dry fill dirt needed for a foundation trench backfill at 95 lbs/cu ft density.
- length: 30
- width: 10
- depth: 12
- density: 95
- waste: 10
- volume: 12.22 cu yd
- weight: 15.68 tons
Frequently Asked Questions
What is fill dirt?
Fill dirt is subsoil taken below the topsoil layer. It contains sand, clay, and rocky gravel, but is free of organic matter. This makes it ideal for structural backfilling because it doesn't decompose or settle like topsoil.
How much does a cubic yard of fill dirt weigh?
A standard cubic yard of dry fill dirt weighs approximately 2,400 to 2,700 pounds (about 1.2 to 1.3 tons). Wet clay or gravelly fill dirt can weigh up to 3,000 pounds per cubic yard.
What is the difference between topsoil and fill dirt?
Topsoil is organic-rich soil used for lawns and gardens. Fill dirt lacks organic matter and nutrients, making it chemically poor for plants but structurally superior for filling deep holes.
How much does soil settle or compact?
Soil naturally compacts after excavation. Loose fill dirt will settle by 10% to 15% under rain and foot traffic, while mechanical tamping can compact soil by 20% or more.
Can I use fill dirt for garden beds?
No. Fill dirt has poor water drainage and lacks organic nutrients. It will pack down tightly like concrete, suffocating plant roots. Only use topsoil or enriched garden soil for gardening.