Trench Volume Calculator

Enter the trench length, width, and depth in metres.

Result

18.00 m³
23.54 yd³
635.66 ft³

How it is calculated

The tool treats the trench as a rectangular box: V = length × width × depth. All three dimensions are in metres, so the main result is in cubic metres. It then converts the same volume: yd³ = m³ / 0.764555 and ft³ = m³ × 35.3147. Results are rounded to two decimals. Each dimension must be greater than zero. The width and depth are single constant values, so the tool does not model sloped or stepped sides, a changing depth, or the extra volume the soil takes up once it is dug (bulking). If your trench has battered sides, enter the average width.

Worked example

A utility trench is 25 m long, 0.6 m wide and 1.2 m deep. The volume is 25 × 0.6 × 1.2 = 18.00 m³. In cubic yards that is 18 / 0.764555 = 23.54 yd³, and in cubic feet 18 × 35.3147 = 635.66 ft³. The tool shows 18.00 m³ as the main result. This is the in-ground volume to excavate, before allowing for how much more space loose soil will need on a truck.

Try this example →

Common mistakes

  • Entering feet or inches into the fields. All three fields are metres: 60 cm must be typed as 0.6, and a trench 4 ft deep as about 1.22.
  • Using the width at the top of the trench for sloped sides. The tool assumes straight walls, so use the average of the top and bottom widths, or the volume will be overstated.
  • Ordering trucks directly from the result. Loose soil takes up more room than undisturbed ground, so the volume to haul is larger than the number shown.
  • Forgetting that the pipe or bedding will take up some of the trench. Backfill needed is the trench volume minus what the pipe and any fixed fill occupy.
  • Averaging a trench whose depth changes along its length with one number. Split it into sections and add the results.

About this calculator

The excavation volume of a trench is simply its length × width × depth, giving a result in cubic metres that this calculator also converts to cubic yards and cubic feet for teams working in imperial units. The math looks trivial, but getting the width and depth right — accounting for sloped sides where soil conditions require them — is what turns this simple product into a usable estimate.

That volume figure drives real decisions on site: how many truckloads of spoil need hauling away, how much bedding material or backfill to order, and how long an excavator crew should budget for the dig. Utility contractors, excavation crews and civil engineers run this calculation before digging trenches for water, sewer, gas or electrical lines to plan equipment, disposal costs and labor time.

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