How Much Fill Dirt Do I Need?
Calculate the exact amount of fill dirt for grading, raising yard elevation, backfilling foundations, and filling low spots. Get results in cubic yards, tons, and truckload estimates.
Quick Answer
A 20×20 ft low area at 6 inches deep needs about 7.4 cubic yards (~11 tons) of fill dirt — less than one full dump truck load (10–14 yd³).
Enter your dimensions above to calculate fill dirt needed.
💡 1 cubic yard of fill dirt covers approximately 54 sq ft at 6 inches deep
How to Calculate Fill Dirt Needed
Formula
Length (ft) × Width (ft) × Depth (in) ÷ 324 = Cubic Yards
Multiply your area's length by width to get square footage. Multiply by fill depth in inches, then divide by 324 to convert to cubic yards. Add 15% to the result to account for compaction — loose fill dirt compacts down when tamped, so you always need more than the raw calculation.
Example
For a 20 ft × 20 ft low area needing 6 inches of fill: 20 × 20 × 6 ÷ 324 = 7.41 cubic yards. Add 15% for compaction: 7.41 × 1.15 ≈ 8.5 cubic yards to order.
Tips & Best Practices
- •Always add 15% to your calculated amount — loose fill compacts 10–15% after tamping and settling.
- •Fill dirt is often free from excavation and construction sites — check Craigslist and Facebook Marketplace under 'free fill dirt'.
- •Always cap fill dirt with 4–6 inches of screened topsoil before seeding, sodding, or planting. Fill dirt has no nutrients.
- •Compact fill in 6-inch lifts using a plate compactor — never leave a full 2–3 ft lift uncompacted.
- •Dump trucks hold 10–14 cubic yards. Plan orders in full truckloads to reduce per-load delivery fees.
Quick Reference
1 cubic yard of fill dirt covers approximately 54 sq ft at 6 inches deep
Fill Dirt Coverage per Cubic Yard
One cubic yard of fill dirt covers approximately 54 square feet at 6 inches deep. Deeper fills for raising grade or backfilling cover less area per yard — use the table below to estimate your order.
These numbers are the in-place volume you need. Always add 15% on top to account for compaction — see the callout below.
| Depth | Coverage per Cubic Yard | Typical Use |
|---|---|---|
| 3 inches | ~108 sq ft | Light leveling, low spot fill |
| 6 inches | ~54 sq ft | Yard grading, general fill |
| 12 inches | ~27 sq ft | Major re-grade, raising elevation 1 ft |
| 18 inches | ~18 sq ft | Significant elevation change |
| 24 inches | ~13.5 sq ft | Major grading, pool fill base |
Always add 15% for compaction
Loose fill dirt compacts 10–15% when tamped. If your calculation shows 7.4 cubic yards, order at least 8.5 yards (7.4 × 1.15). Coming up short means a second delivery fee — which usually costs more than an extra yard of fill.
Planning to cap with topsoil? Use our topsoil calculator → to estimate the 4–6 inch growing layer you'll need on top.
How Fill Dirt Is Sold: Truckload Estimates
Fill dirt is almost always ordered and delivered by the truckload — not by the bag. A standard dump truck holds 10–14 cubic yards. Planning your order around full truckloads cuts down on per-load delivery fees.
Dump Truck Capacities
| Truck Type | Cubic Yards | Approx. Tons |
|---|---|---|
| Tandem-axle dump truck | 10–12 yd³ | ~15–18 tons |
| Tri-axle dump truck | 12–14 yd³ | ~18–21 tons |
| Quad-axle or transfer truck | 16–20 yd³ | ~24–30 tons |
Common Fill Dirt Projects: How Many Truckloads?
The table below shows calculated cubic yards + the 15% compaction buffer already applied (the “order this” amount).
| Project Area | Fill Depth | Order (incl. +15%) | Truckloads |
|---|---|---|---|
| 20×20 ft | 6 inches | ~8.5 yd³ | 1 load |
| 30×40 ft | 6 inches | ~25.6 yd³ | 2–3 loads |
| 50×50 ft | 6 inches | ~53.2 yd³ | 4–6 loads |
| 20×20 ft | 12 inches | ~17.0 yd³ | 2 loads |
| 40×40 ft | 12 inches | ~68.1 yd³ | 5–7 loads |
| 12×24 ft pool void | 5 ft deep | ~61.3 yd³ | 5–7 loads |
Need exact numbers? Use our cubic yards calculator → to convert between units or double-check your estimate.
Fill Dirt vs. Topsoil: Which Do You Need?
These are two different products with different purposes. Using the wrong one wastes money or causes plant failure.
| Property | Fill Dirt | Topsoil |
|---|---|---|
| Source | Subsoil (below topsoil layer) | Top 4–12 inches of natural soil |
| Organic matter | Very little to none | Rich in organic matter |
| Best for | Grading, raising elevation, structural fill | Lawns, gardens, planting beds |
| Can you grow in it? | No — needs topsoil cap | Yes |
| Typical cost | $0–$20/yd³ (often free) | $15–$50/yd³ |
| Compaction needed? | Yes — in 6-inch lifts | Light tamping only |
How to Find Free Fill Dirt
Fill dirt is the one material in landscaping you can often get at no cost. Excavation and construction contractors dig up subsoil regularly and need to dispose of it. That's your opportunity.
Check Craigslist & Facebook Marketplace— search “free fill dirt” in your area. New listings appear weekly near active construction zones.
Contact local excavation contractors — call companies actively digging pool installations, foundations, or road work. Offer them a free dump site (your yard) to save them landfill fees.
Ask at utility projects — water and gas line installations dig up enormous amounts of subsoil. Flag down a supervisor and ask about their disposal plan.
Verify it's clean fill— ask specifically for “clean fill dirt” with no debris, construction waste, or contamination. Clean fill is suitable for residential grading; mixed fill is not.
The standard layering system
For a new lawn after grading: compacted fill dirt base → 4–6 inches of screened topsoil → seed or sod. This gives you grade control from the fill dirt and a nutrient-rich growing layer from the topsoil. Skipping topsoil and trying to grow directly in fill dirt results in thin, struggling grass.
Laying sod after grading? Plan the full material stack with our topsoil calculator and sod calculator →
Frequently Asked Questions
What is fill dirt used for?+
Fill dirt is used for structural and grading projects — raising yard elevation, filling holes and low spots, backfilling around foundations, filling after tree removal, and leveling a yard before adding topsoil. It's subsoil with very little organic matter, making it stable for structural use but unsuitable for growing plants directly.
What's the difference between fill dirt and topsoil?+
Fill dirt is subsoil — the mineral layer below topsoil — with little organic matter or nutrients. It's dense, stable, and used for structural fill and grading. Topsoil is the fertile top 4–12 inches of soil, rich in organic matter, used for growing grass, plants, and gardens. For most yard projects, you'd use fill dirt as the base layer and topsoil as the growing cap on top.
How much does fill dirt cost?+
Fill dirt material often costs $0 — excavation contractors frequently need to dispose of subsoil and will deliver it free or for a small fee. When purchased, fill dirt runs $5–$20 per cubic yard for material. Delivery typically costs $150–$350 per truckload (10–14 yards).
How much fill dirt is in a dump truck?+
A standard tandem-axle dump truck holds 10–12 cubic yards of fill dirt (~15–18 tons). A tri-axle truck holds 12–14 cubic yards (~18–21 tons). For large projects, negotiate for multiple loads from the same contractor to reduce per-load delivery cost.
Do I need to compact fill dirt?+
Yes — always compact fill dirt in 6-inch lifts using a plate compactor or hand tamper. Uncompacted fill settles unevenly over time, causing sinkholes, foundation problems, and unlevel lawns. Compact each layer before adding the next.
How deep of fill dirt do I need before adding topsoil?+
Use fill dirt to reach your target grade, then add 4–6 inches of screened topsoil on top. For example, if you're raising an area by 12 inches total, use 7–8 inches of compacted fill dirt and cap with 4–5 inches of topsoil.