Dirt calculator for Washington
Estimate fill dirt amounts for grade work, excavations, and low areas in cubic yards or tons, with settlement included.
Enter your project dimensions
Fill placed loose commonly settles 10 to 15% in height. Ordering only the measured volume can leave the surface an inch or two below grade after heavy rain, so the calculator includes a 10% settlement allowance. Dry fill dirt weighs about 2,400 lb per cubic yard, or 1.2 tons, and is sold by the yard. Use it below finished grade, not in planting areas. Topsoil is the material for growing and has a separate calculator.
Planning a fill project
- For a raised section, multiply its length and width in feet by the average increase in depth. Where a depression changes depth, measure its deepest and shallowest edges, then calculate from the midpoint.
- Measure holes or trenches by multiplying the opening's length and width by its empty depth, with each dimension in feet.
- To convert cubic feet, divide the result by 27 for yards; multiply yards by 1.2 for tons. Retain the settlement allowance.
Tons = cubic yards × 1.2 · +10% for settling is on by default
Coverage and weight
| Material | Weight per cubic yard | Tons per yard |
|---|---|---|
| Fill dirt (dry) | ≈ 2,400 lb | 1.20 |
| Fill dirt (wet) | up to 3,000 lb | 1.50 |
| Topsoil, for comparison | ≈ 2,200 lb | 1.10 |
| Depth of fill | 1 cubic yard covers | 5 yards cover |
|---|---|---|
| 2 inches | 162 sq ft | 810 sq ft |
| 4 inches | 81 sq ft | 405 sq ft |
| 6 inches | 54 sq ft | 270 sq ft |
| 12 inches | 27 sq ft | 135 sq ft |
Typical fill projects and yardage
| Project | Typical size | Depth | Volume | Weight |
|---|---|---|---|---|
| Raise a low lawn area | 20 x 20 ft | 4" | 4.9 yd³ | 5.9 tons |
| Level a settled depression | 15 x 15 ft, avg 6" | 6" | 4.2 yd³ | 5 tons |
| Backfill a utility trench | 25 ft x 2 ft | 18" | 2.8 yd³ | 3.3 tons |
| Build a landscape berm | 20 x 6 ft | 12" | 4.4 yd³ | 5.3 tons |
| Backfill along a foundation | 60 ft x 2 ft | 10" | 3.7 yd³ | 4.4 tons |
Fill dirt: appropriate uses and limits
Fill dirt is the mineral subsoil beneath topsoil, screened free of rock and debris. It contains little organic matter by design: organic material breaks down over time and can lower the finished surface. Use fill for changing grades, building berms, or backfilling holes and trenches. Areas intended for grass or vegetables need 4 to 6 inches of topsoil above the fill. Reserve topsoil for that upper growing layer.
Accounting for settling before ordering
A second load for the same excavation often results from settlement. Install material in 6 to 8 inch lifts, compacting every lift; at minimum, thoroughly water each one and allow consolidation. For lawn repairs, leave the surface about a half-inch high so it settles flush. Deep structural fill beneath slabs or footings requires thinner lifts, equipment, and an engineer's compaction specification. Keep organic debris out of fill, since buried wood may create a sinkhole five years later.
Ordering dirt during wet weather
Rain changes fill weight, not the volume required for your order. It can change the work schedule, especially west of the Cascades. Wet fill smears rather than compacts and is difficult to move by wheelbarrow, so plan delivery during a dry period. A pile placed high sheds much of the rain, but cover it before storms to make spreading possible days sooner.
Questions from fill dirt projects
What yardage of dirt is needed?
What does one yard of fill dirt weigh?
Definition of fill dirt
What separates fill dirt from topsoil?
How much dirt is required for a hole?
Where do I purchase fill dirt?
What dump-truck capacity is available?
Is compaction needed for fill dirt?
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Fill dirt for grading and backfill, delivered throughout Washington.
