Fill Dirt Calculator
Enter dimensions to calculate fill dirt needed.
Fill Dirt Formula
Measure the area to fill, enter depth, and the calculator converts to cubic yards and estimated tons of fill dirt.
Understanding Fill Dirt
What Is Fill Dirt?
Fill dirt is subsoil - the layer of earth below the nutrient-rich topsoil horizon. It contains minimal organic matter, which makes it dimensionally stable: it does not decompose, settle, or shift over time the way topsoil or compost does. This stability makes fill dirt the preferred material for raising grade, backfilling foundations, and creating level building pads.
Fill Dirt Weight and Volume
| Fill Type | Weight per Cubic Yard | Compacted Weight |
|---|---|---|
| Clean Fill (dry) | 2,000-2,400 lbs | 2,600-3,000 lbs |
| Sandy Fill | 2,200-2,600 lbs | 2,800-3,200 lbs |
| Clay Fill | 2,400-2,800 lbs | 3,000-3,400 lbs |
| Screened Fill | 2,200-2,500 lbs | 2,700-3,100 lbs |
Compaction increases fill dirt density by 20-30%. Order 20-25% more than calculated loose volume for projects requiring compaction.
When to Use Fill Dirt vs. Topsoil
- Fill dirt: Grade changes, foundation backfill, under slabs, retaining wall fill.
- Topsoil: Lawn establishment, garden beds, planting areas.
- Combination: Build up grade with fill dirt, then cap with 4-6 inches of topsoil.
Never use topsoil as structural fill - its organic content decomposes, causing settlement that cracks foundations and buckles pavement.
Estimating Fill Dirt for Common Projects
- Raising yard grade 6 inches over 1,000 sq ft: approximately 18.5 cubic yards.
- Backfilling a basement foundation: 30-60 cubic yards depending on depth.
- Filling a swimming pool: 20-40 cubic yards for a standard residential pool.
- Leveling a building pad (20x30 ft, 12 inches): approximately 22 cubic yards.
Fill Dirt Calculator FAQ
A cubic yard of fill dirt weighs 2,000-2,800 lbs depending on moisture content and soil composition. Dry sandy fill is lighter, while wet clay fill is heavier. Compacted fill weighs 20-30% more than loose fill.
Multiply the area in square feet by the height increase in feet, then divide by 27 to get cubic yards. For 1,000 sq ft raised by 6 inches: 1,000 x 0.5 / 27 = 18.5 cubic yards. Add 20-25% for compaction.
Fill dirt is subsoil with minimal organic matter - stable and does not decompose. Topsoil is the nutrient-rich upper layer that supports plant growth. Fill dirt is for structural purposes; topsoil is for planting.
Yes. Construction sites often give away fill dirt because disposal has a cost. Check local classifieds, contractor networks, and municipal clean fill programs. Verify the material is certified clean fill.
A standard dump truck carries 10-14 cubic yards. Divide your total cubic yards by truck capacity. For 40 cubic yards, you need 3-4 dump truck loads. Delivery fees are - per load.
Yes, for any structural application. Uncompacted fill settles unevenly over time. Compact in 6-8 inch lifts using a plate compactor to achieve 95% standard Proctor density.