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Excavation calculator: dirt volume, swell and truckloads

Calculate the volume of soil to dig out, how much it grows once loosened, its weight and the number of truckloads to haul it away.

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Results

Volume in place (bank)

88.9

Loose volume to haul

111.1

Truckloads
12
Approximate weight
127.4
Hauling cost
$0

Volume for other depths

Volume in place (bank)Loose volume to haul
0.50 ft current22.227.8
1 ft current44.455.6
2 ft current88.9111.1
3 ft current133.3166.7
4 ft current177.8222.2
6 ft current266.7333.3

Estimating an excavation

Whether you are digging a basement, a pool, a footing or leveling a pad for a shed, two numbers matter: the volume in place, which sets the digging time, and the loose volume, which sets how many truckloads you have to haul away. Soil expands once it is dug because air gets between the particles; this is the swell factor. The calculator gives both volumes, the approximate weight and the number of truckloads.

The formulas

  • Bank volume (in place) = length × width × depth
  • Loose volume = bank volume × (1 + swell factor)
  • Truckloads = loose volume ÷ truck capacity, rounded up
  • 1 cubic yard = 27 cubic feet

Typical swell factors:

Material Swell
Sand and gravel 10–15%
Common earth, topsoil 20–30%
Clay 30–40%
Broken rock 50–65%

Once placed and compacted as fill, most soils end up slightly smaller than their bank volume, which is why fill estimates use a shrinkage factor instead.

Worked example

A contractor digs a 40 × 30 ft area 2 ft deep for a slab in common earth, with 10 cubic yard dump trucks.

  1. Bank volume: 40 × 30 × 2 = 2,400 cubic feet, or 88.9 cubic yards.
  2. Loose volume at 25% swell: 111.1 cubic yards.
  3. Truckloads: 111.1 ÷ 10 = 11.1, so 12 loads.
  4. Weight: about 127 tons, which is why weight rather than volume often limits each load.

Volume by depth

For the same 40 × 30 ft area in common earth:

Depth In place Loose
6 in 22.2 yd³ 27.8 yd³
1 ft 44.4 yd³ 55.6 yd³
2 ft 88.9 yd³ 111.1 yd³
3 ft 133.3 yd³ 166.7 yd³
4 ft 177.8 yd³ 222.2 yd³

Before you dig

  • Call 811 at least a few business days ahead to have buried utilities marked; it is free and required in every state.
  • Trenches 5 ft or deeper need a protective system under OSHA rules: sloping, shoring or a trench box.
  • Over-dig for formwork: footings and basement walls usually need 1 to 2 ft of working space on each side, which the calculator does not add.
  • Keep the topsoil separately if you will reuse it for landscaping.
  • Disposal: clean fill is often accepted cheaply or even free; mixed debris costs much more.

Frequently asked questions

How do you calculate excavation volume?

Multiply length × width × depth in feet and divide by 27 to get cubic yards. A 40 × 30 ft area dug 2 ft deep is about 89 cubic yards in place.

What is the swell factor?

Soil takes up more room once dug, because air gets in. Common earth swells about 25%, clay 30 to 40% and broken rock 50% or more, so 89 cubic yards in place become about 111 to haul.

How much dirt fits in a dump truck?

A standard tandem dump truck carries about 10 to 14 cubic yards, but weight often limits the load first: wet clay can reach the legal limit before the bed is full.

How much does a cubic yard of dirt weigh?

Roughly 1.1 to 1.5 US tons depending on soil type and moisture. Sand and gravel are heavier than dry topsoil.

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Results are estimates provided for information purposes. They do not replace professional advice.

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