Stone Calculator

Pick the stone you are actually buying, measure the area, and get cubic yards, an honest tonnage range, and how far a ton goes. Each type carries its own cited conversion — because "stone" weighs anywhere from 1.5 to 2.1 tons per cubic yard depending on which one you mean.

How this is calculated

Shape areas are summed and multiplied by depth: volume = total area × depth (at depth d inches, cubic yards = square feet × d ÷ 324).
Tonnage = volume × the cited conversion for the stone you picked, shown as a range. Nothing is averaged across types.
Coverage per ton = your area ÷ tonnage at your chosen depth.
No compaction allowance is applied here — where one exists, the page names it and links to the calculator that applies it in the right direction.

Data used, with sources

Value	Used as	Source
Crushed stone: 1.75–2.1 tons/cu yd	tonnage for this stone type — has a measured compaction allowance of +36–47 %, not applied on this page	Wisconsin Department of Transportation / Wisconsin Highway Research Program
Driveway gravel: 1.75–2.1 tons/cu yd	tonnage for this stone type — has a measured compaction allowance of +36–47 %, not applied on this page	Wisconsin Department of Transportation / Wisconsin Highway Research Program
River rock: 1.5–1.7 tons/cu yd	tonnage for this stone type — no compaction factor is published for it, so none is applied	Wisconsin Department of Transportation / Wisconsin Highway Research Program
Pea gravel: 1.5–1.7 tons/cu yd	tonnage for this stone type — no compaction factor is published for it, so none is applied	Wisconsin Department of Transportation / Wisconsin Highway Research Program

Tons here means US short tons (2,000 lb).

Why the type is the whole calculation

Take one project — 1,000 square feet at 3 inches, which is 9.26 cubic yards of hole however you fill it — and price it in each of the four stones this page covers:

Crushed stone: 16.2–19.4 tons
Driveway gravel: 16.2–19.4 tons
River rock: 13.9–15.7 tons
Pea gravel: 13.9–15.7 tons

The spread from the lightest estimate to the heaviest is about 5.5 tons on an identical excavation. That is the number a single-conversion "stone calculator" hides, and it is why the first control on this page is the stone type rather than the dimensions.

Choosing between the four

Crushed stone — angular, graded, with fines. It locks together under compaction and carries load, which makes it the base under pavers, patios and slabs. It is also the only kind here you would build a structure on, and the crushed stone calculator adds the compaction allowance this page leaves out.

Driveway gravel is a specific kind of crushed stone: dense-graded with enough fines to crust over, spread as a wearing surface, and the driveway gravel calculator is where its cited loose lift lives. The distinction matters because the clean, single-size stone often sold as "driveway stone" never crusts, and the well-graded subbase products are designed to go under a surface rather than be one.

Pea gravel and river rock are the rounded materials, separated mostly by size — under half an inch, which is what the pea gravel calculator covers, against roughly ¾ to 3 inches. Rounded stone drains freely and is pleasant underfoot, but it will not stay where it is put without an edge, and it does not compact into anything load-bearing. Size decides depth for these: the cited guidance sets rock cover thickness by particle diameter, so the bigger stone needs the deeper, more expensive layer.

Common mistakes

Using one weight for all stone. The cited conversions span 1.5 to 2.1 tons per cubic yard across these four materials alone.
Converting to tons and then adding compaction to the tonnage. Compaction changes volume, not mass. A ton of stone is a ton before and after the roller.
Buying rounded stone for a load-bearing layer. It drains well and compacts to nothing useful.
Ordering to the exact calculated figure. These are published ranges from real measurements; the quarry's own conversion and its scale ticket are what settle the order.

Frequently asked

How many tons of stone do I need?

Volume first, then the conversion for the stone you are actually buying: area in square feet × depth in inches ÷ 324 gives cubic yards, and cubic yards × tons per cubic yard gives tons. The second step is where stone calculators quietly go wrong, because the conversion is not one number. For 9.26 cubic yards — a 1,000 sq ft area at 3 inches — the cited ranges run from 13.9 tons of river rock to 19.4 tons of crushed stone. That is the same hole, filled with the same depth, and up to 5.5 tons of difference on the invoice.

How much does a cubic yard of stone weigh?

There is no single answer, which is why this page makes you pick a type. Dense graded base with fines is cited at 1.75–2.1 tons per compacted cubic yard; the rounded coarse sand and gravel class that pea gravel and river rock are estimated from is 1.50–1.7. Even within one type the range is genuine — it varies with the parent rock, the gradation and the moisture on the day. Any site quoting a single tons-per-yard number for "stone" is quoting an average of materials you are not buying.

Should I order stone by the ton or by the cubic yard?

By the cubic yard when the yard lets you, because volume is the thing you measured — you know exactly how deep you want it over exactly how much ground. Tonnage adds a conversion between what you measured and what you pay for, and that conversion is a range that belongs to the quarry, not to you. Order by the ton when the supplier only sells that way, when the material is going a long distance (freight is priced by weight), or when the load has to respect a vehicle limit — and in that case take the range on this page as a planning figure and the scale ticket as the answer.

Which stone should I use?

Match the stone to the job, not to the picture. Dense-graded crushed stone with fines is the only one of the four that locks up and carries load — it is what goes under pavers and what a driveway surface is made of. Clean single-size stone drains but never binds. Pea gravel and river rock are rounded: comfortable underfoot and good at moving water, but they roll, they need edging, and they are chosen for looks rather than for structure. If your project has to hold something up, you want the graded product; if it has to look good and drain, you want the rounded one.

Why does this page not add a compaction allowance?

Because the correct allowance depends on which direction you are calculating in, and that only makes sense on a page that knows what you are building. Two of these four stones have a measured compaction factor and two have none published at all. Rather than guess, this page gives you honest in-place volume and tonnage and points you at the calculator that handles the allowance properly — the driveway page in particular, where the cited depth is already a loose one and adding an allowance would over-order by about 40 %.

Sources

Weight-Volume Relationships and Conversion Factors for Soils and Aggregates of Wisconsin (WHRP G22-05) — Wisconsin Department of Transportation / Wisconsin Highway Research Program, accessed Jul 31, 2026.
Driving Surface Aggregate Standard and Specification (rev. 18 March 2025) — Pennsylvania State Conservation Commission / Penn State Center for Dirt and Gravel Road Studies, accessed Aug 11, 2026.
Technical Information Sheet #186: Maintenance of Gravel Roads (J. A. Snyder, P.E., Winter 2017) — PennDOT Local Technical Assistance Program (LTAP), accessed Aug 11, 2026.
Conservation Practice Standard: Heavy Use Area Protection (Code 561), September 2020 — USDA Natural Resources Conservation Service, accessed Aug 11, 2026.
Mulches for Nevada Landscapes (A. M. O’Callaghan, SP-06-10, 2006) — University of Nevada, Reno Extension, accessed Aug 11, 2026.
Using Mulches in Utah Landscapes and Gardens (R. Koenig, K. Farrell-Poe, B. Miller, December 2010) — Utah State University Extension, accessed Aug 11, 2026.
CMG GardenNotes #245: Mulching — Colorado State University Extension, accessed Jul 31, 2026.
Water-Wise Landscaping: Mulch — Utah State University Extension, accessed Jul 31, 2026.

Quantities on this page are planning estimates, not engineering advice or a purchase guarantee — product sizes vary by producer, so confirm coverage with your supplier before ordering. Stone under a structure, a pavement, or a retaining wall is governed by your project specification and local code, not by this estimate.