How much fill dirt do I need?
Cubic yards = length × width × depth (ft) ÷ 27 × (1 + compaction allowance)
Fill dirt shrinks as it is compacted, so you need more loose dirt than the finished hole or grade change. Raising a 30 × 20 ft area by 6 inches is 300 cubic feet, about 11.1 cubic yards. With 20% for compaction, order about 13.3 cubic yards.
Fill dirt or topsoil?
| Material | Use it for |
|---|---|
| Fill dirt | Raising grade, filling holes, backfilling walls and foundations |
| Topsoil | The top 4 to 6 inches where grass and plants grow |
| Structural fill | Under slabs and footings, to an engineer's spec |
Typical depths and coverage for fill dirt
How deep to lay fill dirt depends on the job, so treat these depths as common starting points and defer to your plans or the product label. Coverage is how much ground one cubic yard of fill dirt, or one ton, spreads at that depth.
| Project | Depth | 1 cubic yard covers | 1 ton covers |
|---|---|---|---|
| Filling a small low spot | 2 in | 162 sq ft | 162 sq ft |
| Leveling a lawn | 4 in | 81 sq ft | 81 sq ft |
| Building up a pad | 6 in | 54 sq ft | 54 sq ft |
| Backfilling a trench or foundation | 12 in | 27 sq ft | 27 sq ft |
| Raising an area | 24 in | 14 sq ft | 14 sq ft |
Three worked fill dirt jobs
Each job below adds 10% to the fill dirt volume for settling and spills, and converts to tons at 1 tons per cubic yard.
| Job | Size | Cubic yards | With 10% extra | Tons to order |
|---|---|---|---|---|
| Low spot | 15 × 10 ft at 4 in | 1.85 | 2.04 | 2.0 |
| Building pad | 20 × 20 ft at 6 in | 7.41 | 8.15 | 8.1 |
| Backfill | 40 × 4 ft at 12 in | 5.93 | 6.52 | 6.5 |
Before you order fill dirt
- Loose fill compacts when it is rolled or rained on. Fill that is spread 10 to 20% thicker than the final depth is common, and your calculator extra is the way to include that.
- Fill dirt is not topsoil. It is for grade and base, and plants grow poorly in it.
- Moist fill weighs more than dry fill, so a load priced by weight holds fewer yards.
- Ask the supplier what is in the fill, such as clay, rock or debris, before it arrives.
Frequently asked questions
How much does a yard of fill dirt weigh?
About 1 to 1.3 tons, depending on moisture and clay content. Dry fill sits near 1 ton per yard.
How many yards of dirt are in a dump truck?
A standard single-axle dump truck carries about 6 to 10 cubic yards of dirt, and a tandem about 10 to 14, limited by weight more than volume.
How much extra fill dirt should I order for compaction?
About 20% when you compact it in layers. Loose dirt left uncompacted needs less up front but will settle later.
How do I calculate cubic yards of dirt?
Length times width times depth in feet, divided by 27. A 20 by 20 ft area filled 6 inches deep is 7.41 cubic yards.
How many cubic yards in a dump truck?
Many tandem dump trucks carry about 10 to 14 cubic yards of dirt, but the weight limit often governs. Ask the hauler for the load size.
Reference charts
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