Trench excavation calculator
Trench volume with sloped or vertical walls, drawn as you type.
At the invert
Leave blank for vertical walls
Accepts 5' 6" or 5.5
Material and trucksUnlocks loose volume, weight and loads
Unlocks loose volume
Unlocks weight in tons
Unlocks truck loads
We do not fill these in. Swell and density depend on your material, its moisture and how it is dug — a borrowed average is how a haul budget goes wrong.
Trench excavation — bank
Enter the trench dimensions to see the volume.
3 more values:
- Length
- Bottom width
- Depth
- Cross-sectional area
- —
- Bank volume
- —
- Loose volume
- —
- Estimated weight
- —
- Truck loads
- —
- Metric
- —
Needs a swell factor for your material
Needs a loose density
Needs swell and a truck capacity
How this is calculated
A trench is priced from its cross-section. With sloped walls that section is a trapezoid — wider at grade than at the invert — and its area is the mean of the two widths times the depth. Multiplying by the run gives the volume.
Leaving the top width blank collapses the trapezoid to a rectangle, which is exactly what a shored or competent-rock trench with vertical walls is. The calculator does not invent a slope you did not specify.
- Cross-sectional area
((bottom width + top width) ÷ 2) × depth
The trapezoid. With equal widths it reduces to width × depth.
- Bank volume
cross-sectional area × length
In-situ material — what a survey measures, not what fits in a truck.
- Cubic yards
cubic feet ÷ 27
Exactly 27. A cubic yard is three feet cubed, by definition.
- Side slope
(top width − bottom width) ÷ 2 ÷ depth
Reported as run:rise, the way it is called out on a plan. A 1.5:1 slope runs 1.5 ft out for every foot of depth.
- Loose volume
bank volume × (1 + swell)
Only calculated once you give a swell factor for the material you are digging.
- Truck loads
⌈loose volume ÷ truck capacity⌉
Rounded up. If you also give a density and a payload limit, the binding constraint wins and the calculator says which one it was.
What it does not know
- It measures the trench you describe, not the one the ground gives you. Rock, groundwater, soft spots and over-excavation are not in it.
- Sloping is geometry here, not a safety determination. Required slope depends on soil classification and the applicable excavation standard, and that call belongs to your competent person.
- Bedding, pipe displacement and backfill are separate quantities. This calculates the excavation only.
- Swell, density and truck capacity are yours to supply. There are no defaults, because published averages for them span ranges wide enough to change a haul budget by thousands.