How to Use the Soil Volume Conversion Calculator
Soil expands the moment it's excavated (loose/swelled state) and often ends up smaller than its original volume once compacted, so the same amount of earth measures differently at each stage of a job. This calculator takes a volume in any one of the three states — natural, loose, or compacted — and converts it into the other two.
The math relies on two factors: the swell factor (loose volume divided by natural volume) and the compaction factor (compacted volume divided by natural volume). If you enter a natural volume, loose volume is natural x swell factor and compacted volume is natural x compaction factor. If you enter a loose or compacted volume instead, the calculator first backs out the natural volume, then derives the other two from it.
Swell and compaction factors vary significantly by soil type, so accurate figures should come from your project's geotechnical report and soil testing. This calculator simply applies whatever factors you enter, so double-check that your input values are appropriate for the soil on your site before relying on the results.
Frequently Asked Questions
Accurate swell (loose) and shrinkage (compacted) factors should come from a geotechnical report's soil test results. As general references, sandy soils often use a swell factor around 1.1-1.2, clays around 1.2-1.3, and compaction factors typically fall between 0.85 and 0.95 depending on soil type.
Freshly excavated soil is in a loose (swelled) state, so hauling calculations should use loose volume. Once backfilled and compacted, the soil often ends up smaller than its original natural volume. This calculator converts between all three states so you can use the right figure at each stage.