How do I calculate excavation volume?

Multiply the length by the width by the depth of the dig. A trench 20 ft long, 3 ft wide and 4 ft deep is 240 cubic feet, or about 8.9 cubic yards in the ground (6.8 m³). In metric, a dig 6 m × 1 m × 1.2 m is 7.2 cubic metres. That in-ground figure is the bank volume; the pile you haul away is bigger because loose soil takes more room.

What is the difference between bank and loose volume?

Bank volume is the soil sitting undisturbed in the ground. Once you dig it, it breaks up and takes more space — that expansion is the swell, and the result is the loose volume you actually cart away. Common earth swells around 25 percent, so 10 bank yards becomes roughly 12.5 loose yards (10 m³ bank, 12.5 m³ loose); the swell field is editable because it varies a lot with soil type.

How many truckloads of spoil will a dig make?

Work in loose volume, not bank — the truck carries the expanded soil. Divide the loose volume by the capacity of your bin or truck. Wet clay swells and weighs more than dry sand, so if you are billed by weight, enter a density and use the tonnage the tool gives.

Should I add for over-dig?

Often, yes. Hand and machine digs rarely hold the neat lines you draw, and battered trench walls take more than a vertical cut. The over-dig field adds a margin to the bank volume before swell, so both the dig quantity and the haul quantity carry it. Leave it at zero for a tight, shored excavation.

Excavation volume calculator

Longueur

Largeur

Profondeur

Marge de surexcavation

Supplément pour les parois en talus et l’excavation grossière.

Foisonnement

De combien le sol gonfle une fois excavé.

Densité des déblais

t/yd³

Poids à l’état foisonné — laissez vide pour omettre le tonnage.

— yd³

Garder ces résultats

Nous envoyons ce seul courriel par notre fournisseur de courriel et ne gardons pas votre adresse.

These are volumes worked from the dimensions you enter, plus a swell you choose. Soil behaves differently wet and dry and does not read a spec sheet, so treat the spoil and tonnage figures as haulage estimates. This tool does not size shoring, set a safe batter, or judge ground conditions — get those from a competent person on site.

Enter the length, width and depth of the dig and the tool gives you the bank volume — the soil in the ground — then applies the swell to show the loose volume you cart away, and optionally a tonnage. Over-dig, swell and density are all editable so the numbers match your ground and your trucks.

Exemple détaillé

A trench 20 ft × 3 ft × 4 ft is 240 cubic feet, or 240 ÷ 27 ≈ 8.9 bank yards. With 25% swell that loosens to about 11.1 loose yards to haul. At a spoil density of 1.5 tons per loose yard that is roughly 16.7 tons — enough to size the bins before the machine arrives.

In metric: a trench 6 m × 1 m × 1.2 m is 7.2 bank cubic metres (9.4 yd³). With 25% swell that loosens to 9 m³ to haul, and at 1.8 tonnes per loose cubic metre that is about 16.2 tonnes.

Sur le chantier

Footing trench around a house. 136 ft of centreline, 2 ft wide, 3 ft deep: 816 ft³ = 30.2 bank yards (23.1 m³). At 25% swell that is 37.8 loose yards on the pile. Not all of it leaves — the footing and the wall go back in the hole, and what is left over is backfill — so haul the difference, not the lot. Bank yards for the dig, loose yards for the truck, compacted yards for the backfill: three numbers for one hole, and the swell and shrink figures are the soil's, not this page's.

Sizing the bins. 37.8 loose yards in 12-yard bins is 3.15, so four bins — but bins are often capped by weight, not volume. At 1.5 t/yd³ that pile is 57 tons, and a bin rated for 10 tons fills to 6.7 yards before it is overweight, so it is six bins, not four. Ask the bin company both numbers before you order the machine.

A basement, by the load. 30 × 40 × 7 ft = 8,400 ft³ = 311 bank yards, 389 loose. If the tandems on the job carry 10 loose yards, that is 39 loads — at three loads an hour per truck the machine is loading for thirteen hours with one truck, four and a bit with three. That is the number that sets the schedule.

What went wrong?

Quick referencefor digging

Bank / loose / compacted: in the ground · in the truck · back in the hole — three different volumes of the same dirt
Loose: bank × (1 + swell) — the swell figure is the soil's
Trench yards per 100 ft: 2 × 3 ft: 22 · 2 × 4 ft: 30 · 3 × 4 ft: 44 · 4 × 6 ft: 89
Loads: loose yards ÷ what the truck carries — ask, do not assume
A cubic yard: 27 ft³ · 1 m³ = 1,31 yd³
Trench m³ per 10 m: 0,6 × 1 m: 6 · 0,6 × 1,2 m: 7,2 · 1 × 1,5 m: 15
Densité: 1 ton per yd³ = 1.19 tonnes per m³

Waste & overagewhat to add, and why

Trucks are booked on loose volume, so the swell field matters more than the over-dig: 25% is a middle figure for common earth, rock and stiff clay can go higher, and sand hardly swells at all — ask the excavator what this ground does.
Over-dig is real on any hand dig or battered trench; crews carry 5–10% there, in the over-dig field, before the swell is applied.
Round up to whole loads, and remember the last truck goes out part-full at a full-load price.

Mistakes to catchbefore you order

Applying the swell to the bank volume for the fill order — backfill goes in compacted, so bank volume back in the hole is closer to what you need, not loose volume.
Measuring depth from the top of the topsoil after it has been stripped — the dig depth is from the surface you started at.
Typing a width in inches into a feet field for a narrow trench; a 24 in trench typed as 24 ft is a road, not a trench.

What an inspector looks forthe safety officer first, then the building or engineering inspector

On this part of the job

Trench and excavation safety before anything else: sloping, benching or shoring appropriate to the soil, a ladder or safe way out within reach of anyone in the hole, and spoil set back from the edge. This is the item that is enforced hardest and with the least patience.
Utility locates done, marked and still visible, with hand-digging where the locate requires it.
The bottom of the dig: on the material the design assumed, undisturbed, and not softened by water sitting in it overnight.
Dewatering and how the water is being discharged, which is frequently its own permit.
Depth and dimensions against the drawing, taken off a fixed benchmark.

Have this ready

The locate tickets, in date and on site.
The excavation plan and the soil report, if there is one.
Access to the bottom of the excavation that is safe enough for someone else to use.

Every figure an inspector measures against comes from the code your jurisdiction has adopted, the stamped drawing, or the manufacturer's printed instructions — so none of them are printed here. Look the number up in your own book, type it into the tool, and the arithmetic is yours.

La formule

bank = L × W × D · loose = bank × (1 + swell)

The bank volume is a straight box: length times width times depth, divided by 27 to turn cubic feet into cubic yards (in metres it is already cubic metres). Over-dig scales that box up before anything else. Swell is applied last, because soil only expands once it is broken out — multiply by one plus the swell fraction to get the volume the truck sees.

Questions

How do I calculate excavation volume?: Multiply the length by the width by the depth of the dig. A trench 20 ft long, 3 ft wide and 4 ft deep is 240 cubic feet, or about 8.9 cubic yards in the ground (6.8 m³). In metric, a dig 6 m × 1 m × 1.2 m is 7.2 cubic metres. That in-ground figure is the bank volume; the pile you haul away is bigger because loose soil takes more room.
What is the difference between bank and loose volume?: Bank volume is the soil sitting undisturbed in the ground. Once you dig it, it breaks up and takes more space — that expansion is the swell, and the result is the loose volume you actually cart away. Common earth swells around 25 percent, so 10 bank yards becomes roughly 12.5 loose yards (10 m³ bank, 12.5 m³ loose); the swell field is editable because it varies a lot with soil type.
How many truckloads of spoil will a dig make?: Work in loose volume, not bank — the truck carries the expanded soil. Divide the loose volume by the capacity of your bin or truck. Wet clay swells and weighs more than dry sand, so if you are billed by weight, enter a density and use the tonnage the tool gives.
Should I add for over-dig?: Often, yes. Hand and machine digs rarely hold the neat lines you draw, and battered trench walls take more than a vertical cut. The over-dig field adds a margin to the bank volume before swell, so both the dig quantity and the haul quantity carry it. Leave it at zero for a tight, shored excavation.

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