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Calcimator

Backfill Quantity Calculator

Calculate backfill volume accounting for pipe displacement and compaction factor with material tonnage estimates.

Inputs

ft
ft
ft
in

Results

Net Backfill Volume

1,121.46 cu ft

≈ 21 hot tubs

Loose Material Needed

1,401.83 cu ft

≈ 26 hot tubs

Material Weight

72.69 tons

≈ 12 elephants

Gross Trench Volume1,200 cu ft
Pipe Displacement78.54 cu ft
How to Use This Calculator
  1. Enter Trench Length, width, and depth — the calculator computes gross volume.
  2. Set Pipe Diameter and Number of Pipes so their displacement is subtracted from the net fill volume.
  3. Select Soil Type to apply the correct swell factor (loose material expands 10–30% over compacted volume).
  4. Read Net Backfill Volume and Loose Material Needed in cu ft — order material based on the loose figure.
  5. Check Material Weight in tons to size dump trucks and confirm haul costs.

How the result changes with Trench Width

Trench WidthNet Backfill VolumeLoose Material NeededMaterial Weight
2721.46 cu ft901.83 cu ft46.76 tons
72,721.46 cu ft3,401.83 cu ft176.39 tons
135,121.46 cu ft6,401.83 cu ft331.95 tons
187,121.46 cu ft8,901.83 cu ft461.58 tons

What each input means

Trench Length
Length of the trench to be backfilled.
Trench Width
Average width of the trench.
Trench Depth
Depth of the trench from grade.
Pipe Diameter
Outside diameter of pipe installed in the trench (0 if none).
Compaction Factor
Ratio of loose to compacted volume (typically 1.15-1.35 for granular fill).

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Trench Length = 100, Trench Width = 3, Trench Depth = 4, Pipe Diameter = 12 = 5 input(s) provided
  2. Calculate Net Backfill Volume
    Net Backfill Volume
    1121.46 = 1121.46
  3. Calculate Loose Material Needed
    Loose Material Needed
    1401.83 = 1401.83
  4. Calculate Material Weight
    Material Weight
    72.69 = 72.69
  5. Calculate Gross Trench Volume
    Gross Trench Volume
    1200 = 1200
  6. Calculate Pipe Displacement
    Pipe Displacement
    78.54 = 78.54

Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.

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