Glossary

Swell factor

Swell factor is the increase in volume when soil is excavated, from bank cubic yards in the ground to loose cubic yards in the truck.

By IntelCost Team · October 7, 2026

Swell factor is how much soil increases in volume when it is dug out of the ground. Undisturbed soil is measured in bank cubic yards (BCY); once excavated, it breaks up, takes in air and becomes loose cubic yards (LCY).

One yard dug from the ground is not one yard in the truck or one yard in the fill.

How it works

Swell is usually written as a percentage:

Swell (%) = (loose volume - bank volume) / bank volume x 100
Loose volume = bank volume x (1 + swell)

Some references use the inverse, the load factor:

Load factor = bank volume / loose volume = 1 / (1 + swell)

A 25 percent swell is a load factor of 1 / 1.25 = 0.80. Multiply loose yards by the load factor to get back to bank yards.

When to use it

Swell matters wherever soil is moved loose:

Hauling: trucks and scrapers carry loose yards, so the load count comes from LCY, not BCY.
Export and disposal: dump fees are often charged by the load or by loose volume.
Stockpiles: a stockpile takes up loose volume on site.

Excavation itself is still measured and usually paid in bank yards. Mixing the two up is one of the most common earthwork errors.

Example

Say you have 1,000 BCY of excess cut to haul off, a swell of 25 percent and trucks that carry 12 LCY (example values):

Loose volume: 1,000 BCY x 1.25 = 1,250 LCY
Loads: 1,250 LCY / 12 LCY per load = 104.2
Round up: 105 loads

Price the haul on 105 loads, not on the 84 loads you would get from 1,000 / 12 = 83.3 rounded up.

Typical values

Swell depends on the material and how it is dug:

Material	Typical swell, bank to loose
Sand and gravel	Roughly 10 to 15%
Common earth	Roughly 20 to 30%
Clay	Roughly 30 to 40%
Blasted rock	Often 50% or more

These are rough guides only. The actual factors come from the geotechnical report or from the soil on the job; use them whenever you have them.

Swell is not shrink

Swell and shrink describe two different changes from the same starting point:

Factor	From	To	Used for
Swell	Bank	Loose	Hauling and stockpiles
Shrink	Bank	Compacted	Fill and site balance

Shrink is not swell run backwards. Compacted fill is usually denser than the same soil in the bank, so each factor has to be taken from its own source.

In the estimate

Swell turns your cut and fill balance into haul quantities. In IntelCost's Earthwork tab, swell is entered as loose over bank (25 percent is 1.25) and shrink as a factor of extra cut, and the export and import lines come out in their true units. The cut and fill guide shows swell inside a full site balance.