Loose vs Compacted Aggregate: Avoid Double Allowances

The measured finished layer and the delivered loose material are different quantities. Use one explicit conversion from the first to the second, then use a compatible loose density when converting to weight.

By CalcsteadUpdated September 6, 20261 min read

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Apply the allowance to the correct volume

For 1,000 ft² at a 4-inch finished depth, the geometric volume is 333.333 ft³, or 12.346 yd³. An illustrative 15% loose-volume allowance gives 14.198 yd³ to source.

One finished quantity, different stated allowances

These are scenarios, not prescribed compaction factors.

Finished volume	Allowance	Loose volume
10 yd³	0%	10 yd³
10 yd³	10%	11 yd³
10 yd³	15%	11.5 yd³
10 yd³	20%	12 yd³

Do not combine incompatible densities

If a supplier supplies a direct number of tons per finished area and depth, that figure may already incorporate their compaction assumptions. Adding your own loose-volume factor again can inflate the order. Ask what state and moisture condition the density describes.

Keep the purchase increment separate

After calculating the needed loose material, round to the supplier’s order increment or minimum. This is a commercial constraint, not a compaction factor. Record both assumptions so a later quote can be compared against the same quantity basis.

Sources and product references

Mulzer Crushed Stone — aggregate calculator
Supplier context for material-dependent bulk density and estimating limits.
NIST — SI units: volume
Unit relationships; supplier product coverage and prices remain separate inputs.

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