DIRT by SubTrack
Trench volume calculator
Size a trench in bank cubic metres or cubic yards before you call trucks. DIRT uses length, bottom width, depth, and an optional side slope so a battered trench is not billed as a rectangle.
Formula
Volume = length × average width × depth. For a battered trench, average width = bottom width + side-slope × depth, and top width = bottom width + 2 × side-slope × depth. Side slope is run per unit of rise (for example 1:1 is 1).
Worked example
A 40 m run, 0.9 m bottom, 1.2 m deep, 1:1 sides: average width is 2.1 m, volume is 100.8 m³ bank. Convert to loose with the swell calculator before you count trucks.
Metric (m, m³) or imperial (ft, yd³). Output is bank volume until you apply swell.
Open the calculatorField calculators
Estimates for bidding and the truck. Confirm against survey, geotech, and scale tickets before you price.
Trench volume
Excavated volume of a linear trench. Use battered sides for open-cut walls.
Length
m
Bottom width
m
Depth
m
Side slope (H : 1V)
0.5 = 1H:2V. Ignored if sides are vertical.
Excavated volume
72m³
Top width
1.8m
Spoil typically swells 20–30%. Use Swell & shrink to size the stockpile, then Trucks & haul for loads.
Trench volume calculator FAQ
Is trench volume bank or loose?
DIRT reports bank volume from the dimensions you type. Apply a swell factor before you size trucks. Common earth is often about 25% swell. Confirm with the material on site.
How do I account for a battered trench?
Turn on side slope. Average width becomes bottom width plus slope times depth. A vertical trench uses the bottom width only.
Can I use this for a footing or a slab?
For a rectangular prism, leave the sides vertical. For average-end-area or prismoidal runs, use the excavation tab on the main DIRT page.
How does this connect to billing?
The calculator sizes the dirt. SubTrack rate sheets and LEM tickets turn the excavator hours and haul into a signed invoice.
The math is free. The ticket still has to get paid.
DIRT sizes the work. SubTrack turns the labor, iron, and material on the job into a signed LEM against your rate sheet.