Excavation Calculator

An excavation calculator returns the bank (in-ground) volume and the loose (swelled) volume of a dig, plus the number of truck loads needed to haul it away. It multiplies length, width and depth, applies a soil-specific swell factor from 1.15 for sand and gravel to 1.45 for rock, and divides the loose volume by the truck capacity, rounded up.

Last reviewed September 2026Method & sources Report an error

Not to scale.

Loose (Swelled) Volume to Haul

13.89 cu yd

Breakdown
Loose (Swelled) Volume to Haul	13.89 cu yd
Bank (In-Ground) Volume	11.11 cu yd
Truck Loads	2

How to Calculate Excavation

Bank volume is the soil's volume while still undisturbed in the ground. It's a straightforward length × width × depth. Once excavated, that same soil occupies more volume because digging breaks up its natural compaction. This is commonly called "swell" or "bulking." The swell factor is soil-specific, roughly 1.15 for loose sand/gravel up to 1.45 for blasted rock. It converts bank volume to the loose volume that actually needs to be hauled away or has to fit in a stockpile. That's why the same hole produces noticeably more truck loads than its in-ground dimensions alone would suggest.

Example: 10 ft × 10 ft × 3 ft deep excavation in common earth/loam (1.25 swell

A 10 ft × 10 ft × 3 ft deep excavation in common earth/loam (1.25 swell factor), hauled by 10 cu yd trucks: 1. Bank volume: 10 × 10 × 3 = 300 cu ft = 11.11 cu yd 2. Loose volume: 11.11 × 1.25 ≈ 13.89 cu yd 3. Truck loads: ceil(13.89 ÷ 10) = 2 That excavation removes about 13.89 cu yd of loose soil, needing 2 truck loads at 10 cu yd capacity each.

Excavation: Compare Scenarios

Scenario	Loose (Swelled) Volume to Haul	Bank (In-Ground) Volume	Truck Loads
Small (8x8 ft, 2 ft deep utility trench)	5.93 cu yd	4.74 cu yd	1
Medium (10x10 ft, 3 ft deep footing dig)	13.89 cu yd	11.11 cu yd	2
Large (30x20 ft, 6 ft deep basement dig)	166.67 cu yd	133.33 cu yd	17

What Is Excavation?

An excavation calculator converts a planned dig's dimensions into both its bank (in-ground) volume and its loose (swelled) volume once removed, plus the number of truck loads needed to haul that loose volume away. The swell factor is the detail most simple volume calculators miss. It's the reason excavated spoil always seems to be "more than expected."

Excavation: Pros and Cons

Pros

Accounts for soil swell, the single most commonly missed factor in a simple length × width × depth excavation estimate
Soil type is selectable with a representative swell factor for each, rather than one flat figure applied to every job
Reports truck loads directly, useful for coordinating haul-away logistics before work starts

Cons

Swell factors are general planning ranges. Actual swell varies by specific soil moisture content and composition, not just the broad category selected here
Doesn't account for backfill (soil later returned to the hole around a foundation or pipe), which recompacts and doesn't return to its full loose volume. It's a separate calculation from this one
Doesn't size the excavation's dimensions for you (depth/width for a specific footing or utility trench). Those come from your project's own structural or utility requirements

Excavation: What a Pro Checks

Use the loose (swelled) volume, not the bank volume, when ordering trucks or estimating a stockpile's footprint. The same hole always produces more material once dug than its in-ground dimensions suggest.
Treat the soil-type swell factor as a planning range, not an exact figure. Published swell-factor tables disagree with each other, sometimes by a factor of two, so confirm against a geotechnical report or your excavation contractor for anything structural or high-volume.
Don't reuse this calculator's loose volume for backfill. Soil going back into a hole gets compacted as it's placed, so backfill volume is generally closer to the original bank volume instead.

Frequently Asked Questions

What is soil swell (bulking) in excavation?

The volume increase that happens when undisturbed (bank) soil is dug up. Breaking up its natural compaction makes it occupy more space loose than it did in the ground, typically 15-45% more depending on soil type.

How much does excavated soil expand?

It depends on soil type: roughly 15% for loose sand/gravel, 25% for common earth/loam, 30% for clay, and up to 45% for blasted rock, as general planning figures.

How many truck loads will my excavation take?

Divide the loose (swelled) volume, not the bank volume, by your truck's capacity and round up. A 300 cu ft (11.11 cu yd bank) hole in common earth swells to about 13.89 cu yd loose, needing 2 loads at 10 cu yd per truck.

Why is my excavated dirt pile bigger than the hole?

Because of soil swell. The same soil that was tightly compacted in the ground takes up more volume once dug loose. So a hole's excavated spoil pile is always larger than the hole's own volume, sometimes by 25% or more.

Does backfill use the same swell factor as excavation?

No. Backfill is typically compacted back down as it's placed, so it doesn't retain its full loose (swelled) volume. Backfill volume needed is generally closer to (but not always exactly) the original bank volume, not the loose volume calculated here.

Sources

EngineeringToolbox, Soil and Rock - Bulking Factors (reference table of swell/bulking percentages by material; other published tables give meaningfully different ranges) (opens in a new tab)

Concrete & Masonry