Gravel and Aggregate Calculator
Aggregate volume and tonnage for a driveway or base course, with a compaction allowance and the density caveat that decides whether a delivery arrives short.
Gravel & Aggregate Calculator — volume and tonnage
Aggregate is sold by weight but a hole has a volume, and the number that connects them changes with the material and how wet it is. Getting that one factor wrong is how a delivery arrives short.
| Finished volume | — |
|---|---|
| Loose volume to order | — |
| Weight (US tons) | — |
| Weight (metric tonnes) | — |
| Coverage at this depth | — |
| Truck loads (approx) | — |
The volume is exact; the tonnage is an estimate. Indiana DOT publishes a bulk specific gravity for every aggregate source it certifies. For No. 8 alone it lists 267 entries. Drop the two Phoenix Services rows and one that reads 0.006, and the other 264 run from 2.365 to 2.752 (INDOT Aggregate Bulk Specific Gravities, 29 January 2025). At equal gradation, weight per cubic yard follows that. Twenty tons from the heavy quarry is about 14 percent less material than from the light one. That is wider than the 10–15 percent the note above allows.
Compaction is a volume allowance, not a weight one. Compaction changes the space stone fills, not what it weighs. The allowance belongs in one place. Wisconsin DOT's statewide conversion factors are compacted unit weights: 1.75 to 2.1 tons per cubic yard for 3/4-inch dense graded base. A 2023 study for WisDOT measured that material at 1.80 to 1.86, and its compacted-to-loose expansion at 36 to 47 percent (WHRP report G22-05, Table 4.11). Put a compacted tons-per-yard into Custom density, add an allowance on top, and that expansion is counted twice. Divide it out (1.86 over 1.36 to 1.47 is about 1.3), or leave the compacted number and set the allowance to zero. On a loose, delivered figure the allowance is required. Nobody says which one they quoted, so ask.
Water rides on the scale ticket. Caltrans writes the deduction into its standard specification: where aggregate base is paid by weight, the engineer deducts water weighed in excess of the optimum moisture content plus 1 percent (Section 26-1.04). Michigan DOT tells inspectors to cut the load ticket above 8 percent (Construction Manual 302). The overpayment is real; neither clause reaches a driveway delivery. The same WisDOT testing put optimum moisture for 3/4- and 1-1/4-inch base at 5.6 to 8.5 percent. At 7 percent, 1.3 of your 20 tons is water.
Densities here are ordinary dry, loose figures and are approximate. Real density moves
with gradation, moisture and source. The same stone can vary 10–15% between quarries, and wet
material weighs materially more. Ask your supplier for the density of the specific product
before ordering by weight; that number is the whole calculation.
Compaction allowance is the extra loose volume needed to finish at the depth you want. A base compacted
to 15% means you place roughly 1.15 yd³ loose for every 1 yd³ of finished depth. Truck loads
assume about 15 tons per standard tandem load, which varies by jurisdiction and by truck.
Worked example
A 30 × 10 ft path with 4 in of crushed stone: how many yards and tons?
- Volume = 30 × 10 × (4 ÷ 12) = 100 ft³ = 3.7 yd³ compacted.
- Order 15% more to allow for compaction: 4.2 loose yards.
- Crushed stone at about 1.35 t/yd³: roughly 5.7 tons.
3.7 yards in place, 4.2 yards ordered, about 5.7 tons. The density figure is stated on the page, not hidden in the tonnage.
4 values on this page were driven in a browser and compared with independently derived figures on 2026-10-29 (2808 values across 228 calculators site-wide).
Questions
How many tons in a cubic yard of gravel?
About 1.35 US tons for crushed stone and 1.4 for bank-run gravel or sand, the densities the calculator states. A 30 × 10 ft path at 4 inches is 3.7 yd³, about 5 tons.
Why order more than the volume in place?
Compaction: crushed stone loses about 15% of its loose volume under the plate compactor.
Why do 20 tons from two quarries cover different areas?
Because weight per yard follows the source's specific gravity. Indiana DOT's list for No. 8 aggregate runs from 2.365 to 2.752 across 264 sources, so 20 tons from the heavy quarry is about 14% less material than from the light one. Ask the supplier for the density of the exact product.
How much of a gravel ticket can be water?
Enough to matter: Caltrans deducts water weighed above the optimum moisture content plus 1 percent where base is paid by weight (Section 26-1.04), and Michigan DOT tells inspectors to cut the ticket above 8 percent. Neither clause reaches a driveway delivery, so ask what moisture the weight was taken at.