How Much Fill Dirt Do I Need?
Quick answer: cubic yards = area in sq ft × depth in inches ÷ 324. Then add 10–20% (often 15%) because loose fill settles when compacted. One cubic yard covers 324 sq ft at 1 in deep, 81 sq ft at 4 in, or 27 sq ft at 12 in. Example: a 20 × 30 ft low spot filled an average of 4 in needs 7.4 yd³, or about 8.5 yd³ with 15% for compaction.
The 324 shortcut works because one cubic yard is 27 cubic feet, and 27 cubic feet spread 1 inch thick covers 27 × 12 = 324 square feet. If your measurements are all in feet, use length × width × depth in feet ÷ 27 instead. The fill dirt calculator does both and adds compaction, tons, and cost.
How far does a cubic yard of fill dirt go?
| Depth | 1 yd³ covers | Yards per 100 sq ft |
|---|---|---|
| 1 in | 324 sq ft | 0.31 |
| 2 in | 162 sq ft | 0.62 |
| 3 in | 108 sq ft | 0.93 |
| 4 in | 81 sq ft | 1.23 |
| 6 in | 54 sq ft | 1.85 |
| 12 in | 27 sq ft | 3.70 |
These are in-place volumes before compaction. Add your compaction allowance on top.
Fill dirt for common projects
Level a low spot in the yard
Measure the area and estimate the average depth, not the deepest point. A 20 × 30 ft area (600 sq ft) that is 4 in low on average: 600 × 4 ÷ 324 = 7.4 yd³. With 15% compaction, about 8.5 yd³, or roughly 10 tons at 1.2 tons per yard. Finish the top 3–4 in with topsoil if grass will grow there.
Fill a hole
For a round hole, use π × radius² × depth. A 6 ft wide, 3 ft deep hole: 3.14 × 3 × 3 × 3 = 84.8 ft³ ÷ 27 = 3.1 yd³, or about 3.6 yd³ with compaction. Compact in 6–8 in layers so it does not sink later.
Build a berm
A berm with a triangular cross-section has a volume of ½ × base width × height × length. A berm 20 ft long, 8 ft wide at the base, and 3 ft high: 0.5 × 8 × 3 × 20 = 240 ft³ ÷ 27 = 8.9 yd³. Rounded berms with flat tops need more.
Grade soil away from a house
The International Residential Code (R401.3) generally calls for the ground to fall at least 6 in within the first 10 ft from the foundation. Building a wedge 10 ft wide, 6 in deep at the wall and tapering to zero, along a 40 ft wall: 0.5 × 10 × 0.5 × 40 = 100 ft³ ÷ 27 = 3.7 yd³ before compaction. Check your local code and keep fill below siding and weep screeds.
Fill in a pool
Use the average depth. A 16 × 32 ft pool averaging 5 ft deep: 16 × 32 × 5 = 2,560 ft³ ÷ 27 = 94.8 yd³. With 15% compaction, about 109 yd³, roughly 131 tons at 1.2 tons per yard, or about 10 tandem truckloads. Pool removal usually needs a permit and a compaction plan, so follow your local requirements.
Fill dirt vs. topsoil
Fill dirt is subsoil with little organic matter. It compacts well and does not rot or settle much, which makes it right for raising grade, backfilling, and building up under slabs and patios. Topsoil holds nutrients for plants but settles and compacts poorly. A common approach is fill dirt to within 3–4 in of finished grade, then topsoil on top. Use the topsoil calculator for that layer.
Frequently asked questions
How do I calculate how much fill dirt I need?
Multiply the area in square feet by the depth in inches and divide by 324 to get cubic yards. Then add 10–20% for compaction. Example: 600 sq ft × 4 in ÷ 324 = 7.4 yd³, or about 8.5 yd³ with 15%.
How much fill dirt do I need for 100 square feet?
About 0.31 cubic yards per inch of depth: 1.23 yd³ at 4 in, 1.85 yd³ at 6 in, and 3.70 yd³ at 12 in, before compaction.
How much area does a yard of fill dirt cover?
One cubic yard covers 324 sq ft at 1 in deep, 162 sq ft at 2 in, 81 sq ft at 4 in, 54 sq ft at 6 in, and 27 sq ft at 12 in.
How much extra fill dirt should I order for compaction?
Order about 10–20% more than the measured volume, often 15%. Clay-rich or very loose fill and heavy compaction can need more.
How many tons is a yard of fill dirt?
About 1.2 tons per cubic yard on average. Sandy fill runs about 1.15 tons and clay-heavy fill about 1.35 tons or more, depending on moisture.
Related calculators and guides
Sources
- International Residential Code 2021, Section R401.3: Drainage
- Caterpillar: Material Density Tables to Help Estimate Earthwork Volumes
Updated: October 17, 2026 by the YardsCalculator editorial team. Figures are planning estimates; confirm weights, truck capacity, and prices with local suppliers and haulers.