Fill Compaction Calculator
How much material you actually have to dig or buy to build a compacted fill — with shrink factor, lift thickness and roller passes worked out.
Divide, do not multiply
This is the whole calculator in one line. To find how much bank material builds a compacted fill, divide the compacted volume by (1 − shrink factor). At 20% shrinkage, 500 compacted yards needs 625 bank yards.
Multiplying instead — 500 × 0.80 = 400 — is a natural mistake and it leaves you a third short of what you need. The "shortfall if you ignore shrinkage" line above is there specifically so you can see the size of that error on your own numbers.
Lifts are not a detail
Fill is built in layers because compaction energy does not reach far. Eight to twelve inches of loose material per lift suits most rollers; go thicker than the machine can work and the bottom of each lift stays loose. That under-compacted band is invisible on the day and shows up a year later as a dip in the slab or a settled driveway.
Passes per lift is a starting assumption, not a specification. Density testing is what tells you whether you hit 95% Proctor — the number here just helps you plan roller hours.
Where the material comes from
If you are filling from site cut, check the balance on the cut and fill calculator first, and remember the cut number is bank while the fill number is compacted. If you are importing, the loose figure above is what you order and what arrives on the trucks — size the haul with the truck load calculator.
Frequently asked questions
How much fill do I need for a compacted volume?
Divide the compacted volume by one minus the shrink factor. For 500 compacted cubic yards at 20% shrinkage you need 500 ÷ 0.80 = 625 bank cubic yards. Multiplying instead of dividing is the classic error and it leaves you roughly 20% short at the top of the fill.
What does 95% Proctor mean?
It is the compaction standard: the fill must reach 95% of the maximum dry density found for that soil in a laboratory Proctor test. Higher targets mean denser fill, which means more material per placed cubic yard, and usually more passes with the roller.
How thick should each lift be?
Eight to twelve inches of loose material per lift is normal for a walk-behind or small roller, with larger vibratory rollers handling more. Thicker lifts than the machine can work leave the bottom of the lift under-compacted, which is what shows up later as settlement.
Why does the fill keep coming up short?
Usually because the fill quantity came off a cut takeoff without converting states. Cut is bank volume, fill is compacted volume, and the same soil takes less room compacted. Convert before you order, not after the last lift refuses to reach grade.