Materials Calculators

Excavation Calculator

Digging soil out expands it, so you haul away more than the hole's volume. Enter the dig's size for the dirt to remove — in-ground and loose — and the truckloads to haul it.

How deep you're digging.

Soil expands when dug — ~15–30% for common soils (sand low, clay high); heavy clay and rock run higher still.

Dump-truck bed — often 10–16 cu yd; check with your hauler.

To haul (loose)

18.52cu yd

In-ground (bank)
14.81 cu yd
Truckloads
2 loads

How it’s calculated

In-ground (bank) volume = length × width × depth ÷ 27 cubic yards. Loose volume = bank × (1 + swell), since soil bulks up when excavated. Truckloads = loose volume ÷ truck capacity, rounded up. Order the haul-away by the loose figure — the bank number understates how much actually leaves the site.

Worked example

A 20 × 10 ft area dug 2 ft deep: 20 × 10 × 2 = 400 cu ft = 14.8 cu yd in the ground; at 25% swell, 14.8 × 1.25 = 18.5 loose cu yd; in a 12-cu-yd truck, ⌈18.5 ÷ 12⌉ = 2 loads.

FAQs

What is swell (bulking)?
Undisturbed soil is compacted; digging it loosens it so it takes up more space — typically 15–30% more for common soils, with clean sand at the low end and clay at the high end. Heavy clay and especially rock run higher still (blasted rock can swell 50%+), so 30% isn't a hard ceiling. Haul-away and truckloads go by this loose volume, not the in-ground volume, which is why it's an input.
What's the difference between bank and loose volume?
Bank (or in-place) volume is the size of the hole — what you measure on site. Loose volume is that same soil after it's dug and piled, which is larger by the swell factor. Use bank to size the hole and loose to size the truck and disposal.
Anything to do before I dig?
Call 811 (in the US) to have underground utilities located before any digging — it's free and required. Also plan where the spoil goes, and remember backfilling won't return all the soil, since compacted fill takes less volume than the loose pile.

Sources

  • Bank cu yd = L × W × depth ÷ 27 (geometry). Loose = bank × (1 + swell); swell (~15–30% for common soils, higher for heavy clay and rock) is an editable factor, not baked in. Truckloads = loose ÷ capacity, rounded up.

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