Gravel Calculator
Calculate how much gravel, crushed stone or dense-graded base a job needs — in cubic yards, and in the US tons a supplier will actually invoice you for.
Your result
Worked example you can check by hand
Take a driveway 40 feet by 12 feet finished at 4 inches of compacted dense-graded base. 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 conversion of 4,000 lb per cubic yard of aggregate base for crushed stone (Construction and Material Specifications, 1 January 2023 edition, 304.07, Table 304.07-1, used where variable depth is specified; otherwise 304.07 measures aggregate base compacted in place), borrowed here as an ordering estimate, gives 5.93 x 4,000 = 23,720 lb, and 23,720/2,000 = 11.86 US short tons. Order 12 tons. The calculator's default adds a 5 percent allowance on top: 160 x 1.05 = 168 cubic feet, and 168/27 = 6.22 cubic yards, or 12.44 tons at 4,000 lb (the calculator also shows 11.61 tons, using VDOT's 138.2 lb/cu ft). 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. The first says total layer thickness over 4 inches should go down in separate layers; this example's 4 inches sits at that threshold. The second 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 layers.
From volume to the tons you order
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 crushed stone and crushed gravel at 4,000 lb per cubic yard of aggregate base where variable depth is specified (Construction and Material Specifications, 1 January 2023 edition, 304.07, Table 304.07-1); otherwise it measures aggregate base in cubic yards compacted in place. That 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.
Which material, and what it weighs
Where a published range, or a pair of published figures, exists for a material, the calculator uses it rather than a single rule-of-thumb number, because real material 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 |
|---|---|---|
| Dense-graded base, VDOT 21A and Ohio Item 304 type (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 factor Ohio DOT uses to convert weight to pay cubic yards where variable depth is specified. Two published points, not the ends of a survey, and neither is for material specified as crusher run. A load sold as 'crusher run' may be graded to one of these envelopes or to a different one: Virginia's own Crusher Run Aggregate is a separate specification (VDOT Road and Bridge Specifications, 2020 edition, Section 205, sizes 24, 25 and 26), while 21A sits in Section 208, Table II-9. The guide to gravel size numbers sets Ohio Item 304 beside Virginia's crusher run No. 25 and two other gradings. |
138.2 or 148.1 lb/cu ft | VDOT Soils and Aggregate Compaction Field Certification Study Guide, updated 2025, Ch. 7, Form TL-124 Line C (138.2; Aggregate Base Type I, 21A). Ohio DOT Construction and Material Specifications, 1 January 2023 edition (online version 07/17/2026), 304.07, Table 304.07-1: crushed stone 4000 lb/yd³ = 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. No loose-depth row is shown for it: the 30 percent figure comes from FHWA's gravel roads guide, and a dry-rodded density is already a consolidated measurement. Stone tipped and left loose sits below its rodded density, so for that use treat the weight as an upper-end estimate. |
80–120 lb/cu ft | ACI Education Bulletin E1-26, Aggregates for Concrete (March 2026), Table 3.1.2.2c. 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. The depth you enter is taken as the loose depth of stone as it comes out of the bag; no loose-depth row is shown. |
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, spread and not compacted (estimate) This site'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. Choose it for a layer that is spread and left loose: the depth you enter is then the loose depth, and no loose-depth row is shown. |
96–103 lb/cu ft estimate |
Not sourced. VDOT's 138.2 lb/cu ft and Ohio DOT's 4,000 lb per cubic yard of aggregate base (148.1 lb/cu ft; Construction and Material Specifications, 1 January 2023 edition, 304.07, Table 304.07-1, where variable depth is specified), each treated as a compacted figure and reduced by FHWA's '30 percent or greater' volume loss, then rounded down (96.7 and 103.7). |
Gravel density, compaction and conversion data
These are the published figures behind this calculator, with a few that explain them. Each one names the document it came from, including the edition and section, so you can open it and check. The bagged and loose figures the calculator also uses are in the material table above.
| Item | Figure | Source and notes |
|---|---|---|
| Dense-graded base (VDOT 21A), measured field dry density | 138.2 lb/cu ft (1.87 short tons per cubic yard) | VDOT Soils and Aggregate Compaction Field Certification Study Guide, updated 2025, Ch. 7, Form TL-124 (Rev. 07/15), Line C. One worked training example: 21A, Route 17, Campbell County, 6 in. lift, vibratory compaction. |
| Dense-graded base (VDOT 21A), 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 108.2 percent that the uncorrected 127.7 yields 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 Field Certification Study Guide, updated 2025, 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 cubic yard of aggregate base = 2.00 US short tons = 148.1 lb/cu ft | Ohio DOT Construction and Material Specifications, 1 January 2023 edition (online version 07/17/2026), 304.07 Method of Measurement, Table 304.07-1: crushed stone and crushed gravel 4000 lb/yd³, applied 'where variable depth is specified'. A pay-measurement 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 E1-26, Aggregates for Concrete (March 2026), Table 3.1.2.2c. Test method ASTM C29/C29M. The same values appeared in E1-16, Table 3.1.1b. |
| 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. Five documents supply the calculator's sourced figures: VDOT Soils and Aggregate Compaction Field Certification Study Guide (updated 2025), Ohio DOT Construction and Material Specifications (1 January 2023 edition, online version 07/17/2026) Table 304.07-1, ACI Education Bulletin E1-26, the FHWA Gravel Roads Guide FHWA-OTS-15-0002, and the QUIKRETE Pea Pebbles listing for the bagged figure. The loose-gravel figure is this site's own arithmetic and is marked unsourced. 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 Ohio's 4,000 lb is a conversion factor ODOT applies where variable depth is specified, not a measured density. For aggregate mixtures ODOT instead uses 100 percent of the test-section maximum dry density, and for loads more than 2 percent above SSD moisture it calculates cubic yards from dry density and dry weight (304.07). Weights are US short tons of 2,000 lb unless a line says metric.
Why gravel is priced by the ton, and how to get there
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 in cubic yards compacted in place, and where variable depth is specified it converts from weight at 4,000 lb per cubic yard for crushed stone and crushed gravel (Construction and Material Specifications, 1 January 2023 edition, 304.07, Table 304.07-1) - exactly 2.00 short tons at 2,000 lb to the ton.
Loose depth, compacted depth, and when to split the lift
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. Appendix A separately caps each loose horizontal layer at about 4 inches for new surface construction (up to 8 inches with larger compaction equipment), so a 5.7-inch loose spread goes down in two layers. It also asks for a surface layer of at least three inches so a grader has something to work with. Separately from the compaction figure, the calculator adds about 5 percent for spread loss and stone pressed into a soft subgrade - that is a trade habit, not a measured constant.
Water it to the corrected moisture, not the Proctor number
Dense-graded base 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 form marks the 108.2 percent density 'False "High" Density' and the 5.1 percent field moisture 'False "Low" Moisture', because both are judged against Proctor values based on the minus-No. 4 material. 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.
Frequently asked questions
How many tons is a cubic yard of gravel?
For dense-graded base, Ohio DOT's conversion factor (Construction and Material Specifications, 1 January 2023 edition, 304.07, Table 304.07-1, used where variable depth is specified) is 4,000 lb per cubic yard for crushed stone and crushed gravel - 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. The field density in VDOT's Chapter 7 worked example on 21A base, 138.2 lb/cu ft, is 1.87 tons per compacted cubic yard. None of these replaces a scale ticket.
Is the 'two tons per cubic yard' rule of thumb real?
It is real, but it is a specification rather than a measurement. Ohio DOT's Construction and Material Specifications (1 January 2023 edition, 304.07, Table 304.07-1) converts crushed stone and crushed gravel at 4,000 lb per cubic yard of aggregate base where variable depth is specified, which is 2.00 short tons. The same table keys crushed slag to its dry-rodded weight - 3,600 lb below 90 lb/cu ft, 4,000 lb at 90 to 100, 4,500 lb above 100 - and uses 2,800 lb for granulated 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.
How much extra should I order to allow for compaction?
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.
How deep should the gravel layer be?
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 total-thickness threshold, though its 5.7-inch loose spread is over Appendix A's separate cap of about 4 inches loose per layer for new surface construction unless larger compaction equipment is used. 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.
Why is gravel sold by weight when topsoil is sold by 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.
Do I need to wet crusher run or other dense-graded base before compacting it?
Contractors do, and the target is where people go wrong. VDOT's worked example is a 21A aggregate base, not crusher run: the Proctor on the minus-No. 4 fraction reported 8.5 percent optimum (a 6.5 to 10.5 percent band), so the form marks the 5.1 percent field moisture '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 - so watering that material to 8.5 percent would put it outside VDOT's own specification. Virginia's Crusher Run Aggregate specification (Road and Bridge Specifications, 2020 edition, Section 205.03) lists no optimum-moisture requirement; Section 302.03 of the same book requires Class I pipe backfill, which can be crusher run, to be placed at optimum to optimum plus 2 percentage points. A load with a different rock content will have a different corrected optimum. For a homeowner with a plate compactor: damp, never muddy.