Use the Crusher Run Calculator to keep footprint, depth, density and order allowance visible as separate inputs.
What density means on an aggregate order#
Crusher run is a graded crushed aggregate containing larger particles and smaller fines. A supplier's product name alone does not establish its gradation or performance. Ask for the exact specification and intended application.
Bulk density describes the mass occupying a measured bulk volume, including voids between particles. It differs from the density of the solid mineral itself. ASTM C29/C29M covers aggregate bulk density and voids, including defined loose and compacted procedures. A calculator preset is not a laboratory measurement under that standard.
The Vulcan aggregate estimator accepts density separately from project dimensions and distinguishes crushed-stone base/crusher run from coarse aggregate. Its structure illustrates why the material input matters; it does not certify the example below.
Convert density to tons per cubic yard#
For US customary inputs:
short tons/yd³ = density in lb/ft³ × 27 ÷ 2,000
short tons = cubic yards × short tons/yd³
For metric inputs:
tonnes/m³ = density in kg/m³ ÷ 1,000
tonnes = cubic metres × tonnes/m³
The NIST conversion tables provide the unit basis. A US short ton is 2,000 lb; a metric tonne is 1,000 kg. They are different mass units. The yards-to-tons tool supports both systems and reverse conversion.
A completed driveway-base example#
Suppose a measured rectangle is 40 ft × 10 ft, with a specified 4 in finished depth. Use an explicitly hypothetical density of 110 lb/ft³ representing the finished material condition and a separately chosen 10% order allowance.
| Step | Calculation | Result |
|---|---|---|
| Area | 40 × 10 | 400 ft² |
| Depth in feet | 4 ÷ 12 | 0.3333 ft |
| Geometric volume | 400 × 4 ÷ 12 ÷ 27 | 4.9383 yd³ |
| Base mass | 400 × 4 ÷ 12 × 110 ÷ 2,000 | 7.3333 short tons |
| Allowance-adjusted order | 7.3333 × 1.10 | 8.0667 short tons |
The calculator also shows 5.4321 yd³ after that allowance. This is an allowance-adjusted volume on the entered density basis, not a measured loose truck volume. Confirm the supplier's ordering basis before requesting delivery.
If the supplier instead quotes a loose density, use it with a compatible loose volume. Do not multiply a compacted design volume by a loose density and assume that gives the required finished mass.
The same method in metric units#
For a separate illustrative project, a 6 m × 3 m area at 0.10 m finished depth contains 1.8 m³. At an assumed density of 1,800 kg/m³ on that same finished basis:
1.8 m³ × 1,800 kg/m³ = 3,240 kg = 3.24 tonnes
3.24 × 1.10 = 3.564 tonnes with a 10% allowance
Neither density nor allowance is a recommended specification. Replace them with project data.
Loose delivery versus compacted installation#
Compaction changes occupied volume and density. It is not an extra material layer. Ask whether the supplier's tons-per-yard figure describes a loose stockpile, a truck measurement or a defined compacted condition. Also confirm whether moisture is included.
Keep a simple order record: product, measured area, design depth, density, condition, allowance and supplier rounding. If a supplier already includes a placement factor, document it and avoid adding the same factor again as waste.
The required depth, lift sequence and compaction acceptance belong to the design and applicable specification. The quantity calculation cannot decide whether a base suits soil, loading or drainage conditions. Compare the Crushed Stone Calculator when a different aggregate is specified.
Questions to settle before delivery#
- Is the quote per short ton, metric tonne or loose cubic yard?
- Does the density describe the same product and condition as the volume?
- Is the allowance already included in a supplier conversion?
- What delivery minimum, payload and site-access limits apply?
Return to the crusher-run estimate with those answers. Keep full precision through the math, then round the actual order to the supplier's permitted increment.
Sources and worked arithmetic reviewed October 25, 2026. Examples are original hypothetical estimates; no field compaction test or supplier quote is represented.