In-situ volume vs. bulked volume
Bulked volume = In-situ volume × (1 + Bulking%)
Soil in the ground is compacted; once excavated, the loosened material occupies more space than it did undisturbed — this is bulking. A 25% bulking allowance is a standard rule of thumb for typical soils, though it varies by soil type: looser sandy soils bulk less, dense clay can bulk more.
Estimating truckloads
Enter your dump truck's rated capacity and the calculator divides the bulked volume by it, rounding up to a whole number of loads — useful for pricing haul-off or scheduling truck availability on site.
Frequently asked questions
Why does excavated soil take up more space than the hole it came from?
Undisturbed soil is compacted by its own weight and the ground above it over time. Once dug out and loosened, air gaps form between particles, increasing its volume — this is the bulking effect, typically 15-30% depending on soil type.
Should I order backfill based on in-situ or bulked volume?
Use the in-situ (original) volume for backfill — you're filling the same hole you dug, and backfill gets recompacted, so bulking doesn't carry over to that calculation.
What bulking factor should I use for clay vs sandy soil?
25% is a reasonable general default. Sandy or gravelly soils often bulk somewhat less (10-20%); dense clay can bulk more (25-35%). If you know your local soil conditions, adjust the input accordingly.