How to use
- Measure the finished base area and the depth after compaction.
- Enter the compacted weight per volume for that material.
- Enter its loose delivery density from the same supplier.
- Use tons for a weight-based order, or loose yards for a volume-based order.
How the estimate is calculated
Compacted cubic yards = area × finished depth in inches ÷ 324. Multiply that volume by compacted density to obtain tons. Divide those tons by loose density to estimate the loose delivery volume; weight is conserved in this conversion.
Example: 270 sq ft at 4 in finished depth makes 3.33 cu yd compacted. At 1.85 tons per cu yd it needs 6.17 tons. Dividing the unrounded weight by 1.40 tons per loose cu yd gives 4.40 loose cubic yards.
Crusher run and clean stone are not interchangeable
A dense-graded crusher-run base and a clean stone with fewer fines can have different packing behavior. Do not assume the same loose-to-compacted ratio applies to both. Ask the quarry which product and density basis its quote describes.
| Planning factor | Default | Summary basis |
|---|---|---|
| Compacted dense base | 1.85 tons per cu yd | Wisconsin DOT estimate summary |
| Loose aggregate | 1.40 tons per cu yd | Missouri DOT estimate summary |
| Derived volume ratio | 1.85 ÷ 1.40 = 1.3214 | Arithmetic from the entered defaults |
The default loose volume is about 32.14% larger than the finished volume. These source summaries are preliminary planning references, not an official project-specific expansion requirement. No extra waste or over-excavation allowance is added.
Compaction lifts and ordering by weight
Plan placement in lifts suitable for the material and your compaction equipment; the calculator does not specify lift thickness or test compaction. Ordering by the calculated tons avoids confusing a loose yard with a finished yard, but moisture and the supplier’s density still affect the estimate. Confirm the quantity basis before accepting delivery.
Common mistakes
- Entering loose pile depth where finished compacted depth is requested.
- Multiplying tons by loose density instead of dividing.
- Adding the loose and compacted yards together as two separate purchases.
Sources
Wisconsin DOT dense-base summary and Missouri DOT loose-aggregate estimating summary provide the planning defaults. Both were checked only as search summaries; no code section or verified official requirement is claimed here.
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Frequently asked questions
Why are loose yards greater than compacted yards?
With the default densities, the same weight occupies more space in its loose state. The volume ratio comes from compacted density divided by loose density.
Should I buy both volumes shown?
No. They describe the same estimated material in two states. Choose the ordering basis used by your supplier.
Does this add a fixed compaction percentage?
It derives the conversion from your two density inputs instead of adding a separate fixed percentage.
Can I use clean drainage stone?
Only with density values appropriate to that stone and its intended placement. The default dense-base behavior may not apply.
Is extra for uneven excavation included?
No. The calculation uses the exact area and finished depth supplied. Discuss any allowance for site variation separately.