Excavation & Backfill Volume Calculator

Earthwork volumes are measured in three soil states. Each state reflects how the material behaves during excavation, hauling, and placement — and the conversion between them depends on swell and shrink factors specific to your soil type.

• Bank (BCY — bank cubic yards) — in-situ soil as it exists in the ground before disturbance. Excavation takeoffs start here: length × width × depth, divided by 27.
• Loose (LCY — loose cubic yards) — excavated soil after it is dug and loosened. Volume increases due to swell (bulking). Haul-off trucks and stockpiles are measured in loose yards: BCY × (1 + Swell% ÷ 100).
• Compacted (CCY — compacted cubic yards) — placed and mechanically compacted fill in its final in-place density. Backfill space after deducting structural voids is measured in compacted yards. Loose material to order accounts for shrink: CCY ÷ (1 − Shrink% ÷ 100).

Compacted backfill must be placed in controlled lifts and compacted to a target density — typically 90–95% of Standard Proctor maximum dry density for structural backfill around foundations and utilities.

Lift thickness: Place backfill in lifts no thicker than 4–8 inches loose before compaction. Thick lifts prevent adequate densification at the bottom of the lift and are a common cause of settlement.

Compaction equipment: Use a plate compactor or hand tamper for narrow utility trenches and tight areas around footings. Vibratory rollers or sheepsfoot rollers suit larger open excavations. Match equipment energy to lift thickness and soil type.

Moisture-density (Proctor test): Compaction efficiency peaks at optimum moisture content. Too dry and particles will not knit; too wet and pore water carries load instead of soil grains. A Standard Proctor test defines the moisture-density curve for your borrow material — field moisture should be within a few percent of optimum before compaction.

Structural void interaction: Foundations, footings, pipe, and utility structures occupy volume within the excavation that will not be backfilled with native soil. Enter that combined volume as Structural Void — the calculator subtracts it from gross excavation before computing CCY and loose backfill LCY. Haul-off volume is based on total excavation regardless of void, since all disturbed soil must still be removed.