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Generated on: July 20, 2026 at 09:33 PM

Excavation Volume Calculator

Inputs

Length5 m
Width3 m
Depth1.5 m
Swell factor25 %
Truck capacity8 m³

This estimate assumes a simple rectangular excavation with vertical sides and a single swell factor. Real digs vary with sloped or benched walls, mixed soil types, water, and over-excavation, and truck capacity can be limited by weight as well as volume. Treat the result as a planning figure and confirm quantities with your contractor or haulage provider.

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Lifestyle

Excavation Volume Calculator

Estimate the volume of soil to dig out for a trench, footing, or pit, and how many truckloads it takes to haul away. Bank volume comes from length times width times depth; a swell (bulking) factor turns it into the looser volume that has to be trucked off site.

Inputs

≥ 0.01 m
≥ 0.01 m
≥ 0.01 m
%
0 – 100 %
≥ 0.01 m³

Results

Enter a value to see results.

Details

Volume Breakdown

\begin{aligned} V &= L \times W \times D \\ &= 5 \times 3 \times 1.5 \\ &= ? \end{aligned}
\begin{aligned} Q &= V (1 + s) \\ &= ? \times (1 + 25) \\ &= ? \end{aligned}
\begin{aligned} N &= \left\lceil \frac{Q}{c} \right\rceil \\ &= \left\lceil \frac{?}{8} \right\rceil \\ &= ? \end{aligned}

A 5 m × 3 m × 1.5 m excavation holds ... of bank soil. With 25 % swell it loosens to ..., which fills about ... truckload(s) at 8 m³ per truck.

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Excavation Volume

Digging a trench, footing, pond, or foundation starts with a simple question: how much soil is coming out, and how many trips does it take to haul away? The volume of the hole is easy geometry, but the pile of spoil beside it is always bigger than the hole itself. Accounting for that expansion is the difference between ordering the right number of trucks and paying for a wasted trip.

Bank volume: the size of the hole

The soil in place, before anything is disturbed, sits at its bank volume. For a rectangular excavation that is just length times width times depth:

V=L×W×DV = L \times W \times D

This is the volume of the void you are creating, and the figure to use for backfill or for sizing the excavation itself.

Loose volume: soil that has swelled

Once soil is dug out it breaks up and no longer packs as tightly, so the loose pile takes more room than the hole. The swell (or bulking) factor is the fraction of that expansion — roughly 10 to 15% for sand, about 25% for ordinary soil, and 40% or more for clay and rock. Multiply the bank volume by one plus the swell factor:

Q=V(1+s)Q = V (1 + s)

The loose volume, not the bank volume, is what has to be trucked off site.

Truckloads

Divide the loose volume by the capacity of one truck and round up, since a partial load still ties up a whole trip:

N=⌈Qc⌉N = \left\lceil \frac{Q}{c} \right\rceil

Worked example

Take an excavation 16 feet long, 10 feet wide, and 5 feet deep5 metres long, 3 metres wide, and 1.5 metres deep, with a 25% swell factor and a truck that carries 10 cubic yards8 cubic metres per load.

The bank volume is length times width times depth:

V=16×10×5=800 cu ft≈29.6 cu ydV = 16 \times 10 \times 5 = 800 \text{ cu ft} \approx 29.6 \text{ cu yd}

Applying a 25% swell factor gives the loose volume:

Q=29.6×1.25≈37.0 cu ydQ = 29.6 \times 1.25 \approx 37.0 \text{ cu yd}

At 10 cubic yards per truck, that is:

N=⌈37.010⌉=⌈3.7⌉=4 truckloadsN = \left\lceil \frac{37.0}{10} \right\rceil = \lceil 3.7 \rceil = 4 \text{ truckloads}
V=5×3×1.5=22.5 m3V = 5 \times 3 \times 1.5 = 22.5 \text{ m}^3

Applying a 25% swell factor gives the loose volume:

Q=22.5×1.25=28.125 m3Q = 22.5 \times 1.25 = 28.125 \text{ m}^3

At 8 cubic metres per truck, that is:

N=⌈28.1258⌉=⌈3.52⌉=4 truckloadsN = \left\lceil \frac{28.125}{8} \right\rceil = \lceil 3.52 \rceil = 4 \text{ truckloads}

So a modest-looking hole still fills four trucks once the soil loosens up.

Choosing a swell factor and reading the result

The swell factor is the figure that most changes the haulage cost, and it depends on the ground. Dry sand and gravel barely expand; damp topsoil and loam sit near a quarter; heavy clay, cemented soils, and broken rock swell most. When the material is mixed or unknown, lean toward the higher end so you do not run short of trucks.

Real excavations are rarely tidy boxes. Sloped or benched sidewalls, over-digging to reach firm ground, water in the trench, and rock all change the volume, and a truck's usable capacity is sometimes limited by weight rather than by how much fits in the bed — wet soil is heavy. Use this estimate to plan and to sanity-check a quote, then confirm the final numbers with the contractor or haulage provider who will do the work.

For related site-work estimates, see the Paver Patio Calculator for surfacing the finished area and the Mulch & Garden Soil Calculator for filling a bed once the digging is done.

Frequently Asked Questions (FAQ)

What is a swell (bulking) factor?

Soil in the ground is compacted by its own weight. When you dig it out, it breaks apart and the loose material takes up more space than the hole it came from. The swell factor is the percentage of that expansion.

Typical figures are about 10 to 15 percent for sand and gravel, around 25 percent for ordinary soil, and 40 percent or more for stiff clay or blasted rock. The wetter and more cohesive the material, the more it swells. Use a figure that matches your ground, and lean higher if you are unsure.

How much soil fits in one truckload?

Capacity varies widely by vehicle. A small tandem dump truck often carries roughly 8 to 12 cubic yards, a tri-axle more, and a pickup with a trailer far less — sometimes only 1 to 2 cubic yards.

Capacity can also be limited by weight rather than volume, since wet soil is heavy. Check the rated capacity of the truck you will actually use, and remember that the loose volume, not the bank volume, is what fills the bed.

What is the difference between bank and loose volume?

Bank volume is the amount of soil measured in place, in the ground: length times width times depth. It is the size of the hole you are digging.

Loose volume is that same soil after excavation, once it has swelled. Because the material expands, the loose volume is always larger. Order haulage and disposal by loose volume, but size the hole and any backfill by bank volume.

Disclaimer

This estimate assumes a simple rectangular excavation with vertical sides and a single swell factor. Real digs vary with sloped or benched walls, mixed soil types, water, and over-excavation, and truck capacity can be limited by weight as well as volume. Treat the result as a planning figure and confirm quantities with your contractor or haulage provider.

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