How much dirt do I need?
Multiply the area by the depth you need to fill, then add an allowance if the dirt will be compacted. Use the shape that matches the hole: a rectangle for a low strip of lawn, a circle for a stump or post hole.
cubic yards = length (ft) × width (ft) × depth (in) ÷ 324
A 10 × 8 ft low spot filled 6 inches is 40 cubic feet, or 1.48 cubic yards. A stump hole 3 ft across and 2 ft deep is 3.1416 × 1.5² × 2 = 14.1 cubic feet, or 0.52 cubic yards. To measure odd shapes, see how to measure irregular areas.
| Area (ft) | 2 in | 4 in | 6 in | 12 in |
|---|---|---|---|---|
| 10 × 10 | 0.62 | 1.23 | 1.85 | 3.7 |
| 10 × 20 | 1.23 | 2.47 | 3.7 | 7.41 |
| 20 × 20 | 2.47 | 4.94 | 7.41 | 14.81 |
| 20 × 40 | 4.94 | 9.88 | 14.81 | 29.63 |
Dirt calculator in yards: bank, loose and compacted
Order about 1.39 loose cubic yards of loam (1.59 of clay) for every cubic yard of firmly compacted fill.
The same dirt takes up three different volumes. In the ground it is bank volume; once dug and delivered it has swelled to loose volume; rolled or tamped it shrinks to compacted volume. The US Army's earthmoving tables give these factors:[1]
| Soil | Bank → loose | Loose → compacted | Compacted → loose (order factor) |
|---|---|---|---|
| Loam (common earth) | 1.25 | 0.72 | 1.39 |
| Clay | 1.43 | 0.63 | 1.59 |
So if you need a cubic yard of firmly compacted loam fill, order about 1.39 loose cubic yards; for clay, about 1.59. Enter that as a compaction allowance of 39% or 59% in the calculator. For a lawn low spot that will only settle naturally, a smaller margin is more realistic; there is no published figure for garden settling, so choose your own with the allowance field.
Digging out and filling backDirt you dig from a 1 cubic yard hole comes out as about 1.25 loose yards of loam or 1.43 of clay.[1] Plan room for the spoil pile.
Dirt calculator in tons
A loose cubic yard of dirt weighs about 1,900–2,200 lb dry and 2,800–3,200 lb wet for loam, and 1,700–2,000 lb dry or 2,400–3,000 lb wet for clay.[1]
| Loose material | lb per yd³ | US tons per yd³ | tonnes per m³ |
|---|---|---|---|
| Loam or topsoil, dry | 1,900–2,200 | 0.95–1.1 | 1.13–1.31 |
| Loam or topsoil, wet | 2,800–3,200 | 1.4–1.6 | 1.66–1.9 |
| Clay, dry | 1,700–2,000 | 0.85–1 | 1.01–1.19 |
| Clay, wet | 2,400–3,000 | 1.2–1.5 | 1.42–1.78 |
A New Mexico state conversion table uses a single factor of 0.80 tons per cubic yard for topsoil or fill dirt,[2] lighter than the dry range above, and a UK producer gives about 1.5 tonnes per cubic meter for its standard topsoil.[3] The spread is the point: ask your supplier how they weigh a yard, and use the tons to yards calculator to compare quotes. The yard of dirt weight guide explains the differences.
Fill dirt or topsoil?
Fill dirt raises or levels ground; topsoil is the layer plants grow in. Use fill for the bulk of a deep hole and finish the top with topsoil where grass or plants will grow. For a new lawn, Penn State recommends at least 4–6 inches of settled topsoil on top.[4] The topsoil calculator sizes that top layer, and the raised bed soil calculator handles beds.
Metric
Switch to meters and the dirt calculator works in m³ and tonnes. One cubic yard is 0.7646 m³, so the factors and weights above apply unchanged per unit of volume.[5] A 3 × 2.5 m area filled 15 cm deep is 1.125 m³.
How much does a yard of dirt cost?
A yard of fill dirt costs your supplier's price per cubic yard plus delivery; when it is sold by the ton, remember that a loose yard of loam weighs about 0.95–1.1 US tons dry and 1.4–1.6 wet.[1] Enter your quotes in the price fields to compare the per-yard and per-ton totals for your own hole or low spot.
Frequently asked questions
How many yards of dirt do I need?
Square feet × depth in inches ÷ 324. A 20 × 20 ft area raised 4 inches needs 4.94 cubic yards, before any compaction allowance.
How much does a yard of fill dirt weigh?
About 1,900–2,200 lb dry and 2,800–3,200 lb wet for loose loam.[1]
How much dirt do I need to fill a hole?
Hole volume plus a compaction allowance. A round hole 3 ft across and 2 ft deep holds 14.1 cu ft (0.52 cubic yards); to compact loam into it firmly, order about 1.39 times that, or 0.73 cubic yards.
Does fill dirt compact?
Yes. Loose loam compacts to about 72% of its volume and clay to about 63%.[1]
Sources
- FM 5-434 Earthmoving Operations, Tables 1-1 and 1-2 (material weights, swell and conversion factors)
- Conversion Factors for Construction Materials and Common Minerals (from BLM Handbook H-3890-1)
- Calculating topsoil requirements
- Lawn Establishment
- NIST Handbook 44, Appendix C: General Tables of Units of Measurement