# How much dirt do I need?

Computes the fill dirt to fill a rectangular or round area to a depth, with extra for compaction, in cubic yards, cubic feet and cubic metres, its weight in tons, and the cost.

- Page: https://www.acalculator.org/construction/dirt-calculator
- JSON spec: https://www.acalculator.org/construction/dirt-calculator.json
- Version: 64293bd67dcf

## Default answer

Example with the default inputs (Area shape Rectangle, Length 20 ft, Width 10 ft, Depth 6 in, Extra for compaction 10%, Weight per cubic yard (tons) 1.2): Order 4.07 yd³ of dirt (110 ft³), about 4.89 tons.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| shape | Area shape | Whether the area to fill is a rectangle or a circle. |
| l | Length | The length of the area to fill. |
| w | Width | The width of the area to fill. |
| d | Diameter | The diameter of a round hole or area. |
| depth | Depth | How deep to fill, after the dirt is packed down. |
| extra | Extra for compaction | Loose dirt to add, in percent, because it packs down: 10% to 15% for ordinary grading. |
| wt | Weight per cubic yard (tons) | How many US tons one cubic yard of your dirt weighs: about 1.2 to 1.5. Ask your supplier. |
| price | Price per cubic yard | What one cubic yard of dirt costs, delivered. Leave empty to skip the cost. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| cubicYards | Cubic yards | The dirt to order, in cubic yards (27 cubic feet each). |
| cubicFeet | Cubic feet | The dirt to order, in cubic feet. |
| cubicMeters | Cubic metres | The dirt to order, in cubic metres. |
| tons | Weight (US tons) | Cubic yards × the weight per cubic yard, in tons of 2,000 lb. |
| tonnes | Weight (tonnes) | The same weight in metric tonnes of 1,000 kg. |
| cost | Cost | Cubic yards × the price per cubic yard. |

## Method

Volume = length × width × depth (or π × diameter² ÷ 4 × depth) × (1 + extra ÷ 100); cubic yards = cubic feet ÷ 27; tons = cubic yards × tons per cubic yard; tonnes = tons × 0.90718474.

## Assumptions

- Extra for compaction is 10% by default (NeedsDirt: 10% to 15% for non-structural grading, 15% to 30% for structural fill).
- One cubic yard of fill dirt weighs 1.2 US tons by default (NeedsDirt: 1.2 to 1.5 tons, by moisture and make-up). Type your supplier’s figure.
- The area is filled level to the depth you type, with straight sides.

## Worked examples

1. shape = rect, l = 6.096, w = 3.048, depth = 0.1524, extra = 10%, wt = 1.2 gives cubicFeet = 110, cubicYards = 4.074074, tons = 4.888889. Source: NeedsDirt, How to Calculate Fill Dirt Needed (add 10 to 15% for non-structural grading; 1.2 to 1.5 tons per cubic yard), https://needsdirt.com/guides/how-to-calculate-fill-dirt-needed-contractor-s-complete-guide.
2. shape = rect, l = 8.2296, w = 0.3048, depth = 0.3048, extra = 0%, wt = 1.5, price = $30.00 gives cubicYards = 1, tons = 1.5, tonnes = 1.360777, cost = $30.00. Source: NIST Handbook 44 (2026), Appendix C (1 yd³ = 27 ft³; 1 short ton = 2,000 lb = 0.90718474 t).
3. shape = rect, l = 5, w = 4, depth = 0.3, extra = 15%, wt = 1.2 gives cubicMeters = 6.9, cubicYards = 9.024859. Source: NIST Handbook 44 (2026), Appendix C (1 yd³ = 0.764554857984 m³).
4. shape = circle, d = 3.048, depth = 0.6096, extra = 0%, wt = 1.2 gives cubicFeet = 157.079633, cubicYards = 5.817764.

## FAQ

### How do I calculate how much dirt I need?

Multiply length × width × depth, all in feet, to get cubic feet, then divide by 27 for cubic yards. A 20 × 10 ft area filled 6 in (0.5 ft) deep needs 100 ft³, or 3.70 yd³. With 10% extra for compaction: 110 ft³, or 4.07 yd³.

### Why order extra dirt for compaction?

Loose dirt from a truck packs down when it is spread, rolled and watered, so the packed fill takes less room than the loose dirt you buy. NeedsDirt suggests adding 10% to 15% for ordinary grading and 15% to 30% for structural fill. The calculator adds 10% by default.

### How much does a cubic yard of dirt weigh?

About 1.2 to 1.5 US tons (2,400 to 3,000 lb), depending on how wet it is and how much clay it holds. The calculator uses 1.2 tons by default; type your supplier’s figure for a better estimate.

### How many cubic feet are in a cubic yard?

A cubic yard is 3 ft × 3 ft × 3 ft = 27 ft³, about 0.765 m³. Bulk dirt is sold by the cubic yard or by the ton.

### How do I calculate dirt for a round hole?

Use the area of a circle, π × diameter² ÷ 4, times the depth. A hole 10 ft across and 2 ft deep holds π × 100 ÷ 4 × 2 = 157.08 ft³, or 5.82 yd³.

### Is fill dirt the same as topsoil?

No. Fill dirt is subsoil used to raise or level ground and fill holes; topsoil is the richer top layer for planting. For garden beds, use the soil calculator.

## Sources

- NeedsDirt, How to Calculate Fill Dirt Needed: A Contractor’s Complete Guide (add 10–15% for non-structural grading and 15–30% for structural fill; a cubic yard weighs 1.2 to 1.5 tons). https://needsdirt.com/guides/how-to-calculate-fill-dirt-needed-contractor-s-complete-guide (retrieved 2026-10-01)
- Engineering ToolBox, Dirt and Mud - Densities (dirt, loose dry 76 lb/ft³; clay, dry 100 lb/ft³). https://www.engineeringtoolbox.com/dirt-mud-densities-d_1727.html (retrieved 2026-10-01)
- NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement: 1 yd³ = 27 ft³; 1 ft = 0.3048 m; 1 short ton = 2,000 lb; 1 lb = 0.45359237 kg. https://www.nist.gov/document/2026-nist-handbook-44-appendix-c (retrieved 2026-10-01)