Fill Dirt Calculator
Calculate tons of fill dirt needed to grade or fill a low area, plus total cost at your price per ton.
How this calculator works
Fill dirt is sold by the ton, so this calculator converts your area and fill depth into cubic yards, then multiplies by fill dirt’s density (1.1 tons per cubic yard) — lighter than gravel or crushed stone, but denser than loose topsoil. Waste isn’t factored in here, since fill jobs are usually measured to a target grade rather than covered with a buffer percentage.
Formula: Cubic yards = (Length ft × Width ft × Depth ft) ÷ 27. Tons = Cubic yards × 1.1.
Worked example
A 20 ft × 10 ft low spot filled 6 inches deep, $25/ton:
- Depth in feet: 6 ÷ 12 = 0.5 ft
- Cubic yards: (20 × 10 × 0.5) ÷ 27 ≈ 3.70 yd³
- Tons: 3.70 × 1.1 = 4.07 tons
- At $25/ton, that’s $101.85.
Coverage reference
| Area × depth | Fill dirt needed |
|---|---|
| 10 ft × 10 ft @ 6 in | 2.0 tons |
| 20 ft × 10 ft @ 6 in | 4.1 tons |
| 30 ft × 20 ft @ 12 in | 24.4 tons |
How to measure your area
Measure the footprint of the area you’re bringing up to grade, and estimate the average fill depth rather than the deepest point — a low spot is rarely a uniform depth across its whole area. If the depth varies a lot, split the area into sections with roughly consistent depth and calculate each separately.
Frequently asked questions
What's the difference between fill dirt and topsoil?
Fill dirt is subsoil with the organic matter, roots, and debris removed — it's meant to raise grade or fill a hole, not grow anything. Topsoil is the nutrient-rich, organic-heavy layer meant for planting. Don't use fill dirt as a planting bed; use it under one.
Why is fill dirt priced lower than topsoil?
Fill dirt requires less processing and screening than topsoil, and it isn't valued for fertility, so suppliers typically price it lower, often $20-30 per ton compared to $30-50+ for screened topsoil.
Does fill dirt compact after it's delivered?
Yes, significantly. Loose fill dirt settles as it compacts under its own weight and moisture changes, so deep fills (6+ inches) are often ordered with 10-15% extra material or filled and compacted in layers to reach the target finished grade.
How deep is a typical fill dirt project?
Grading low spots or filling a small depression is often done at 6 inches. Larger regrading jobs or filling an old foundation excavation can run 12 inches or more, usually placed and compacted in lifts.
Can I use fill dirt under a lawn?
Yes, but you'll need a layer of topsoil on top before seeding or sodding — fill dirt alone won't support healthy grass growth since it lacks organic content and nutrients.
Estimates only. Verify quantities with your supplier before purchasing.