Earthwork
Earthwork Swell and Shrink Calculator
Soil occupies more volume when excavated (swell) and less when compacted (shrinkage) than it did in the ground. Use this to convert bank yards to haul and fill quantities.
Formula
Loose = bank × (1 + swell). Compacted = bank × (1 - shrinkage). Bank needed for a compacted fill = fill ÷ (1 - shrinkage), and the loose haul volume = that bank volume × (1 + swell).
Worked example
1,000 bank yd³ of common earth with 25% swell and 10% shrinkage: loose = 1,250 yd³, compacted = 900 yd³. To build 500 compacted yd³ of fill you need 500 ÷ 0.90 = 555.6 bank yd³, hauled as 694.4 loose yd³.
Assumptions and limits
- Factors depend on soil type, moisture and compaction effort; use project geotechnical data when available.
- Rock can have negative shrinkage (it bulks even when compacted).
Frequently asked questions
What is the difference between bank, loose and compacted yards?
Bank yards are measured in place before digging, loose yards in the truck or stockpile, and compacted yards in the finished fill.
What are typical shrinkage values?
Common earth often shrinks about 10% to 20% from bank to compacted, clays somewhat more, while sand and gravel shrink less.
Why does my fill take more dirt than the hole I dug?
Because fill is compacted denser than the natural ground, each compacted yard requires more than one bank yard.