An aggregate delivery arrives as a weight on a scale ticket and leaves the stockpile as a volume on site. The bridge between the two numbers is the product's bulk density in its stated condition. Enter that density with matching units and the converter returns the other quantity.
How do you convert aggregate weight to volume?
Divide the weight by the bulk density. To convert volume to weight, multiply the volume by the same number.
Volume = weight ÷ bulk density
Weight = volume × bulk density
The density must describe the same material in the same condition as the quantity you are converting. A loose dry value cannot convert a compacted wet volume. The converter checks that the units match; it cannot check that the number belongs to your product.
What does the converter need from you?
| Input | What to enter | Why it matters |
|---|---|---|
| Conversion direction | Weight to volume, or volume to weight | Chooses the formula and the unit list |
| Quantity and unit | The ticket weight or the site volume, in kg, tonnes, lb, short tons, m³, litres, yd³, or ft³ | Sets the starting side of the conversion |
| Bulk density and unit | The product's value in kg/m³, t/m³, lb/ft³, lb/yd³, or short tons/yd³ | The single number that links weight and volume |
| Material condition (optional) | Loose, compacted, delivered, dry, or wet, as stated on the source | Recorded beside the result so the number stays checkable |
The density field starts blank and stays required. The converter has no default density, because the correct value depends on the product, source, and condition.
Which formulas does the converter use?
The converter moves every entry into one canonical form, calculates at full precision, then displays up to 3 decimal places.
| Relationship | Constant used | Where it applies |
|---|---|---|
| 1 U.S. short ton = 2,000 lb | 907.18474 kg per short ton | Imperial weight entries |
| 1 metric tonne = 1,000 kg | Exact | Metric weight entries |
| 1 yd³ = 27 ft³ | Exact | Imperial volume entries |
| 1 m³ = 1,000 L | Exact | Metric volume entries |
| 1 yd³ = 0.764554857984 m³ | NIST Handbook 44 value | Cross-system checks |
| 1 lb/ft³ = 16.01846337396014 kg/m³ | Derived from 1 lb and 1 ft³ | Density unit entries |
Switching the unit system converts the entered quantity and density to the new system's primary units, clears the result, and requires a fresh calculation.
Worked imperial example
A ticket shows 20 short tons of crushed stone. The supplier record states 1.4 short tons/yd³ for that product in its delivered condition.
- Weight in pounds: 20 × 2,000 = 40,000 lb.
- Density in pounds per cubic yard: 1.4 × 2,000 = 2,800 lb/yd³.
- Volume: 40,000 ÷ 2,800 = 14.285714... yd³.
- Equivalent: 14.285714 × 27 = 385.714... ft³.
Converted result: 14.286 yd³, or 385.714 ft³. The density, its unit, and the delivered condition travel with the result on the page.
Worked metric example
A stockpile survey gives 13.333 m³ of gravel. The project record states 1,500 kg/m³ loose, dry basis, for that product.
- Weight: 13.333 × 1,500 = 19,999.5 kg.
- Equivalent: 19,999.5 ÷ 1,000 = 19.9995 metric tonnes.
Converted result: 19,999.5 kg, or 20.000 metric tonnes after display rounding. The same arithmetic runs in reverse: 20,000 kg ÷ 1,500 kg/m³ = 13.333 m³.
Which density number should you enter?
Use the most project-specific evidence available, in this order: the supplier or plant record for the exact product, a project test per ASTM C29/C29M stating the condition, and only then a recognized reference table with its stated limits.
Caterpillar's reference tables show why one product has several valid numbers. Dry gravel reads 1,510 kg/m³ (2,550 lb/yd³) loose and 1,690 kg/m³ (2,850 lb/yd³) bank; wet 6–50 mm gravel reads 2,020 kg/m³ (3,400 lb/yd³) loose and 2,260 kg/m³ (3,800 lb/yd³) bank. These are reference values, not project numbers. The table footnote states that weight varies with moisture content, grain size, and degree of compaction, and that tests are required to determine exact material characteristics.
The density number guide explains how to read a label and check a suspicious value. The supplier ticket guide covers the weight side: gross, tare, net, and the ton or tonne unit.
Write 1,500 kg/m³ loose, dry basis rather than 1,500 alone. A number without its state and unit cannot be checked later, and it cannot be reused for a different condition.
Common conversion mistakes
- Entering a lb/ft³ density against a short-ton weight without matching the units.
- Using a compacted density to convert a loose stockpile volume, or the reverse.
- Copying a density from an unlabeled online table with no material, state, or moisture information.
- Treating a wet density as interchangeable with a dry one; water adds mass to the same pile.
- Converting a ticket weight and assuming the result proves the placed volume on site.
- Rounding the density or the quantity before comparing the conversion with the ticket.
- Mixing bank, loose, and delivered numbers in one calculation.
The common mistakes guide and the worked example walk through these errors with site context.
What the converter does not do
The converter changes units through your density number. It does not choose the material, adjust for moisture, convert between loose and compacted states, or add swell, shrinkage, waste, allowance, or contingency. Those are separate calculations with separate evidence.
It does not set a truck or trailer load. Vehicle payload, axle limits, body volume, loading method, moisture, driver responsibilities, and current law control transport. The ordering guide covers the supplier-order steps that follow a conversion.
For quantities that start from site dimensions rather than a known weight or volume, use the Gravel Calculator, which measures area and depth first.
Sources and scope
- ASTM C29/C29M, Bulk Density ("Unit Weight") and Voids in Aggregate, scope summary: bulk density is the mass per unit volume in compacted or loose condition; results are used for mass/volume relationships in purchase agreements; accessed 17 October 2026.
- Caterpillar, Material Density Tables to Help Estimate Earthwork Volumes: per-material and per-state reference densities; the footnote states weight varies with moisture content, grain size, and degree of compaction and requires testing for exact values; accessed 17 October 2026.
- Al-Mustansiriyah University, concrete technology lecture notes: bulk density converts quantities by mass to quantities by volume; it depends on size distribution, particle shape, and degree of compaction; accessed 11 October 2026.
- NIST Handbook 44 (2026), Appendix C: cubic-foot, cubic-yard, litre, and cubic-metre relationships; accessed 17 October 2026.
Source scope: ASTM supports the bulk-density definition and the loose-versus-compacted distinction. Caterpillar supports the per-state reference-density illustration and the no-universal-density boundary. NIST supports the stated conversions. Project drawings, specifications, surveys, supplier records, test data, local weights-and-measures rules, and responsible people control the accepted density, moisture basis, and final project quantity.
Review note: Calculation logic and independent automated fixtures passed internal review. Saleem Sial is the research and editorial owner. Waseem Sial, External Reviewer and Engineer, remains listed for ongoing external review; no completed external-review date is claimed.
