Soil Swell Factor Table
Quick answer: swell is how much soil expands when it is dug. Loose yards = bank yards × (1 + swell %). Typical swell: sand and gravel about 12%, loam and common earth 23–27%, clay 22–25%, topsoil about 43%. Example: 100 bank yd³ of common earth at 25% swell becomes 125 loose yd³ to haul.
Every earthwork estimate deals with three volumes for the same soil. Mixing them up is the most common reason for ordering too few trucks or too little fill.
- Bank cubic yards (BCY): soil in its natural, undisturbed state. This is what you measure in the hole.
- Loose cubic yards (LCY): soil after digging. Air gets between the particles, so it takes up more space. This is what trucks haul.
- Compacted cubic yards (CCY): soil placed as fill and compacted. It is denser and usually smaller than the bank volume.
Swell factor by soil type
Swell is calculated from Caterpillar’s published load factors (loose weight ÷ bank weight): swell % = (1 ÷ load factor − 1) × 100.
| Material | Bank (lb/yd³) | Loose (lb/yd³) | Load factor | Swell |
|---|---|---|---|---|
| Sand & gravel, wet | 3,750 | 3,400 | 0.91 | 10% |
| Sand (dry, damp, or wet) | 2,700–3,500 | 2,400–3,100 | 0.89 | 12% |
| Gravel, dry or pit-run | 2,850–3,650 | 2,550–3,250 | 0.89 | 12% |
| Clay & gravel, dry | 2,800 | 2,400 | 0.85 | 18% |
| Clay, natural bed | 3,400 | 2,800 | 0.82 | 22% |
| Earth, loam | 2,600 | 2,100 | 0.81 | 23% |
| Clay, dry | 3,100 | 2,500 | 0.81 | 23% |
| Earth, dry packed | 3,200 | 2,550 | 0.80 | 25% |
| Clay, wet | 3,500 | 2,800 | 0.80 | 25% |
| Earth, wet excavated | 3,400 | 2,700 | 0.79 | 27% |
| Sand & clay, loose | 3,400 | 2,700 | 0.79 | 27% |
| Topsoil | 2,300 | 1,600 | 0.70 | 43% |
| Crushed stone | 4,500 | 2,700 | 0.60 | 67% |
Moisture, grain size, and how the soil is dug all change swell. Use these as planning values and replace them with site test data for bids.
Conversion formulas
- Bank → loose: LCY = BCY × (1 + swell). Equivalently, LCY = BCY ÷ load factor.
- Loose → bank: BCY = LCY × load factor.
- Bank → compacted: CCY = BCY × (1 − shrinkage).
What about shrinkage?
Shrinkage compares compacted fill to the original bank volume. It depends on the soil and, above all, on the compaction specification (for example, a percentage of Proctor density). Construction texts give about 5–12% for sand and gravel. Earth and clay usually shrink more, and the figure varies widely with moisture and compaction effort. On engineered fill, the geotechnical report governs. The 10% used in the example below is only an illustration.
Worked example: cut, haul, and fill
You excavate 100 bank yd³ of dry packed earth (25% swell) and haul it away.
- Loose volume to haul: 100 × 1.25 = 125 LCY.
- Truck loads: dry packed earth weighs about 2,550 lb per loose yard, so a tandem with a 15-ton payload carries about 11.8 yd³. 125 ÷ 11.8 = 10.6, so plan 11 loads.
- If the same soil were placed back as compacted fill with 10% shrinkage, it would fill about 100 × 0.90 = 90 CCY.
Going the other way: to build 90 compacted yd³ of fill from this soil, you need about 100 bank yd³ from the borrow site, which arrives as about 125 loose yd³ of truck volume.
The dirt removal, trench, and excavation calculators all have a swell option for haul volume.
Frequently asked questions
What is a soil swell factor?
It is the percentage a soil expands when excavated. Loose volume equals bank volume × (1 + swell). Common earth swells about 25%, so 10 bank yards become about 12.5 loose yards.
What is the swell factor for clay?
Caterpillar’s load factors give about 22% for natural-bed clay, 23% for dry clay, and 25% for wet clay. Clay mixed with gravel swells about 18%.
What is the swell factor for sand and gravel?
About 10–12%. Caterpillar lists a load factor of 0.89 for sand and gravel (12% swell) and 0.91 for wet sand and gravel (10% swell).
What is the difference between bank and loose cubic yards?
Bank cubic yards measure soil undisturbed in the ground. Loose cubic yards measure the same soil after digging, when it takes more space. You measure bank yards and haul loose yards.
How do I convert loose yards back to bank yards?
Multiply loose cubic yards by the load factor. For common earth with a 0.80 load factor, 125 loose yards × 0.80 = 100 bank yards.
Related calculators and guides
Sources
- Caterpillar: Material Density Tables to Help Estimate Earthwork Volumes
- Salahaddin University: Excavation lecture notes (swell and shrinkage ranges)
Updated: October 17, 2026 by the YardsCalculator editorial team. Figures are planning estimates; confirm weights, truck capacity, and prices with local suppliers and haulers.