Calculate how much gravel, crushed stone or crusher run a job needs — in cubic yards, and in the US tons a supplier will actually invoice you for.
Take a driveway 40 feet by 12 feet finished at 4 inches of compacted crusher run. Area is 40 x 12 = 480 square feet. Four inches is 4/12 = 0.333 feet, so 480 x 0.333 = 160 cubic feet, and 160/27 = 5.93 cubic yards compacted in place. Ohio DOT's pay conversion of 4,000 lb per compacted cubic yard gives 5.93 x 4,000 = 23,720 lb, and 23,720/2,000 = 11.86 US short tons. Order 12 tons. Then check the spread rather than the purchase: at FHWA's 30 percent volume loss you must lay 4/0.70 = 5.7 inches loose to finish at 4. FHWA's Appendix A has two different 4-inch rules and this example invokes the first: total finished layer thickness over 4 inches should go down in separate layers. The second rule caps a loose horizontal layer at about 4 inches for new surface construction, rising to 8 inches with larger compaction equipment - so a 5.7 inch loose spread needs either heavier plant or two passes.
Gravel is bought by the ton, so the conversion that matters is weight per compacted cubic yard, not volume on its own. Ohio DOT converts aggregate base at 4,000 lb per compacted cubic yard where variable depth is specified, which is 2.00 US short tons (one short ton = 2,000 lb). Multiply compacted cubic yards by 2.00 for tons to order. Loose material is a separate quantity: FHWA reports that ordinary compaction removes 30 percent or more of the volume, so finished depth divided by 0.70 gives the loose depth you actually have to spread.
The calculator uses a density range per material, not a single number, because real aggregate varies with moisture, grading and how hard it has been compacted. Where a figure could not be traced to a published document it is labelled as an estimate.
| Material | Density used | Source |
|---|---|---|
| Crusher run / dense-graded base (two published points, not a range) Dense-graded crushed stone with its fines left in — VDOT 21A, Ohio DOT Item 304. The low figure is one measured field dry density after vibratory compaction of a 6-inch lift; the high figure is the rate Ohio DOT pays against. Two published points, not the ends of a survey. |
138.2–148.1 lb/cu ft | VDOT Soils and Aggregate Compaction, 2023 ed., Ch. 7, Form TL-124 Line C (138.2). Ohio DOT CMS Item 304.07 conversion table, 4,000 lb/compacted cu yd = 148.1 lb/cu ft. |
| Washed coarse aggregate / clean concrete stone (dry-rodded) Clean washed stone screened to one size band with the fines removed, for concrete, drains and pipe bedding. ACI's figure is dry-rodded, so it counts the air between the stones. The band is wide because it spans every normalweight rock ACI recognises — prefer your supplier's own number. |
80–120 lb/cu ft | ACI Education Bulletin E1-16, Aggregates for Concrete (2016), Table 3.1.1b. Test method ASTM C29/C29M. |
| Bagged pea gravel (as packaged) Rounded washed stone in bags, for paths, drain trenches and dog runs. This is a package ratio, not a laboratory density: one named product holds half a cubic foot at 50 lb net. No top size or ASTM size number could be confirmed from a text-readable sheet, so neither is claimed. |
100 lb/cu ft | QUIKRETE HardScapes Pea Pebbles, part 117510, 0.5 cu ft / 50 lb net (Ace item 7305592, read 22 Sep 2026). 50 / 0.5 = 100 lb/cu ft. |
| Loose gravel as tipped from the truck (estimate) The author's estimate, not a sourced figure — arithmetic on two other numbers. Because FHWA writes 'or greater', these are ceilings rather than a constant. Weigh the load: a scale ticket beats this figure every time. |
96–103 lb/cu ft estimate |
Not sourced. Ohio DOT's 4,000 lb/compacted cu yd reduced by FHWA's '30 percent or greater' volume loss. |
These are the figures this calculator uses. Each one names the document it came from, including the edition and table, so you can open it and check.
| Item | Figure | Source and notes |
|---|---|---|
| Crusher run, measured field dry density | 138.2 lb/cu ft (1.87 short tons per cubic yard) | VDOT Soils and Aggregate Compaction, 2023 ed., Ch. 7, Form TL-124 (Rev. 07/15), Line C. One worked training example: 21A, Route 17, Campbell County, 6 in. lift, vibratory compaction. |
| Crusher run, rock-corrected maximum dry density | 142.6 lb/cu ft | Same manual, Ch. 7, Form TL-124 Line H. Corrects the 127.7 lb/cu ft minus-No. 4 Proctor for 47% plus-No. 4 rock at bulk SG 2.63. The uncorrected 127.7 is annotated 'False High Density' on the form. |
| Corrected optimum moisture for that aggregate | 5.1% (acceptable band 3.1-7.1%) | Same manual, Chapter 7, Calculation #3 / Form TL-124 Line I: [(0.47 x 0.013) + (0.53 x 0.085)] x 100, which the manual rounds term by term to 0.006 + 0.045 = 0.051, i.e. 5.1%. |
| Moisture tolerance, aggregates | Optimum plus or minus 2 percentage points | VDOT Soils and Aggregate Compaction, 2023 edition, Chapter 2, 'Moisture Specifications'. Soils and subgrade get a different rule, plus or minus 20 percent of optimum. |
| Aggregate base pay conversion, crushed stone and crushed gravel | 4,000 lb per compacted cubic yard = 2.00 US short tons = 148.1 lb/cu ft | Ohio DOT Construction and Material Specifications, Item 304.07 Method of Measurement, weight-to-volume conversion table (2013 CMS online text; the same table appears in the 2008 CMS). A pay factor, not a measured density. |
| Dry-rodded bulk density, coarse aggregate | 80-120 lb/cu ft (1,280-1,920 kg/cu m) | ACI Education Bulletin E1-16, Aggregates for Concrete (2016), Table 3.1.1b. Test method ASTM C29/C29M. Same values appear as Table 2 of the older E1-07. |
| Volume lost to ordinary compaction | 30 percent or greater | FHWA Gravel Roads Construction & Maintenance Guide, FHWA-OTS-15-0002 (Aug 2015), §3.19. In full: "In many parts of the country this will result in 30 percent or greater reduction in volume." Both the hedge and 'or greater' matter — anything derived from this is a ceiling. |
| Thickness above which gravel must be placed in separate layers | 4 in. total layer thickness | Same guide, Appendix A: "If total layer thickness will exceed 4-inches, the gravel should be placed in separate layers." Guidance, not a requirement. Appendix A separately caps a loose horizontal layer near 4 in. for new surface construction. |
| US crushed stone sold or used by producers, 2025 | 1,500 million metric tons (estimated), about 1.65 billion US short tons | USGS Mineral Commodity Summaries, Feb 2026, Stone (Crushed), Salient Statistics, row 2025e. Chapter header: 'Data in million metric tons unless otherwise specified'. USGS publishes no point of sale, so none is claimed. |
Each figure was read out of the document named beside it. Four do the work: VDOT Soils and Aggregate Compaction (2023 ed.), Ohio DOT CMS Item 304.07, ACI Education Bulletin E1-16, and the FHWA Gravel Roads Guide FHWA-OTS-15-0002. Two caveats: the VDOT numbers come from a single completed Form TL-124 printed as a teaching example, not a body of field data; and the Ohio DOT table was read in the 2013 CMS and cross-checked against 2008, where it is identical — we could not retrieve a machine-readable 2023 edition. Weights are US short tons of 2,000 lb unless a line says metric.
Gravel leaves the quarry across a weighbridge, and the scale ticket is the one number you and the supplier can both check afterwards. That is deliberate. ACI records that the bulk density of coarse aggregate rises as it wets, while damp sand bulks and loses density, so a cubic yard sitting in a truck box is not a repeatable quantity of rock - the weight is stable, the loose volume is not. Topsoil is sold the opposite way round because what a gardener is actually buying is bed depth, and settled volume is the thing that matters to them. Both trades are right about their own material. To turn your volume into a purchase order, use a weight per compacted cubic yard. Ohio DOT measures aggregate base as cubic yards compacted in place and converts at 4,000 lb per cubic yard for crushed stone and crushed gravel - exactly 2.00 short tons at 2,000 lb to the ton.
The depth you spread is not the depth you finish with. The FHWA's Gravel Roads guide says ordinary compaction - the material being placed, routine blade maintenance, rainfall and traffic passing over it - produces a 30 percent or greater reduction in volume. Divide your finished depth by 0.70 and you get the loose depth you must build: a 4-inch compacted base needs roughly 5.7 inches of loose material. Because the guide says 'or greater', treat that as the least you will lose, not a fixed shrinkage. The same guide sets the lift rule: if total layer thickness will exceed 4 inches, the gravel should be placed in separate layers in order to achieve good compaction and density. It says nothing about the material being uncompacted at that thickness. It also asks for a surface layer of at least three inches so a grader has something to work with. On top of the compaction figure we add about 5 percent for spread loss and stone pressed into a soft subgrade - that is a trade habit, not a measured constant.
Crusher run contains coarse rock, and a standard Proctor only tests what passes the No. 4 sieve. VDOT's training manual walks one example all the way through to show what happens if you stop there. The minus-No. 4 Proctor gave a maximum dry density of 127.7 lb per cubic foot and an optimum moisture of 8.5 percent; the manual prints 'False High Density' and 'False Low Moisture' on the form beside them. Correcting for 47 percent plus-No. 4 rock at a bulk specific gravity of 2.63 moves maximum dry density to 142.6 and optimum moisture to 5.1 percent. The consequences are real ones. That field density of 138.2 reads 108.2 percent against the uncorrected figure and 96.9 percent against the corrected one, against a 95.0 percent minimum. VDOT allows aggregate optimum plus or minus 2 percentage points, a band of 3.1 to 7.1 percent, so watering to 8.5 percent lands outside it. The plus or minus 20 percent rule belongs to soils and subgrade.
For dense-graded base compacted in place, Ohio DOT's own pay conversion is 4,000 lb per cubic yard - 2.00 US short tons, at 2,000 lb to the ton. A loose cubic yard tipped from a truck is lighter, because the FHWA puts the volume lost to ordinary compaction at 30 percent or greater; that caps a loose yard at about 2,800 lb, or 1.40 tons. VDOT's one measured field density, 138.2 lb/cu ft, is 1.87 tons per compacted cubic yard. None of these replaces a scale ticket.
It is real, but it is a specification rather than a measurement. Ohio DOT CMS Item 304.07 converts crushed stone and crushed gravel at 4,000 lb per compacted cubic yard, which is 2.00 short tons. The very same table uses 3,600 lb for light crushed slag and 4,500 lb for heavy slag, so the rule tracks what the rock is, not a universal density. Use it to order; do not use it to argue with a weighbridge.
Compaction is not waste, and it is far larger than any waste allowance. FHWA reports a 30 percent or greater volume reduction from ordinary compaction, so divide your finished depth by 0.70 to get the loose depth - 4 inches finished needs about 5.7 inches spread. Separately from that, this calculator adds about 5 percent for spread loss and stone pressed into a soft subgrade. The 30 percent is sourced to FHWA; the 5 percent is a trade convention with no measured source behind it.
FHWA asks for a surface layer of at least three inches so a grader has material to work with, and says any total layer thickness exceeding 4 inches should be placed in separate layers. Our 4-inch default sits exactly at that threshold: it is the deepest single lift the guide permits without splitting. Treat it as a site default rather than a figure lifted from a published thickness table - FHWA's own thickness guidance (Table 3) is keyed to subgrade support and truck volume.
Because a different quantity is unstable in each case. ACI records that coarse aggregate gets denser with moisture while damp fine aggregate bulks and gets lighter, so a loose cubic yard of aggregate is not a repeatable amount of rock - the scale is the only honest unit. Topsoil is bought for the depth it makes across a bed, so volume is the thing the buyer actually wants, and selling it by weight would make the price swing with how wet the pile happened to be.
Contractors do, and the target is where people go wrong. In VDOT's worked example the Proctor on the minus-No. 4 fraction reported 8.5 percent optimum, which the manual labels 'False Low Moisture'. Corrected for 47 percent rock, optimum is 5.1 percent, and VDOT's aggregate tolerance is plus or minus 2 percentage points - a band of 3.1 to 7.1 percent. Watering to 8.5 percent would put you outside VDOT's own specification. For a homeowner with a plate compactor: damp, never muddy.