Multiply length × width × depth in feet, divide by 27 for cubic yards, then multiply by 1.45 to get tons of #57 stone. A 20 × 10 ft area at 3 inches deep needs about 1.85 cubic yards — roughly 2.7 tons.
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#57 Stone Calculator Guide
#57 stone is the most-specified crushed stone in America — the washed, 3/4-inch-average aggregate that fills French drains, backfills foundations, beds concrete slabs, and tops gravel driveways. The “57” is a gradation number from the ASTM/AASHTO system describing a blend that passes a 1-inch sieve and stays on a #4 sieve; it says nothing about the rock type, which is usually whatever your local quarry crushes — limestone, granite, or trap rock. This calculator uses its standard density of 1.45 tons per cubic yard.
What makes #57 special is what’s missing: fines. Washed clean of dust and sand, it keeps 36–42% of its volume as open voids no matter how hard you compact it. Those voids are the product.
What Is #57 Stone Used For?
| Application | Typical depth | Why #57 wins |
|---|---|---|
| French drains | 3+ in around pipe | Open voids move water to the pipe fast |
| Foundation backfill | per plan | Drains hydrostatic pressure away from walls |
| Under concrete slabs | 4 in | Capillary break stops moisture wicking up |
| Driveway surface course | 2–3 in | Clean look, no mud, sheds rain |
| Permeable paving reservoir | 6+ in | Stores stormwater in the void space |
“Does #57 Compact?” — The Question That Decides Projects
Roll it all day and #57 will seat and interlock — but it will never densify, because there are no fines to fill the voids. Engineers treat placed #57 as effectively self-compacted at about 4% settlement. The practical consequences: it’s a superb drainage layer and a legitimate open-graded base under slabs, but it is not the material to compact into a structural driveway base. That job belongs to crusher run, whose fines lock solid. On driveways the pairing is classic: compacted crusher run for strength, #57 on top for a clean, draining surface.
One more practical note: because the stones are uniform and loose, #57 is hard to walk on in thick layers and migrates on slopes. Keep surface courses to 2–3 inches and edge them well.
#57 vs #67 and Neighbors
#67 is #57’s slightly smaller sibling (3/4-inch top size, most pieces near 1/2 inch) — a touch easier to rake and level, common in concrete mixes and pipe bedding. #8 and #9 are smaller still, used as chip layers over open-graded bases. If a spec calls for one and the quarry stocks another, match the gradation sheet rather than the number — state-to-state naming is famously inconsistent. For the load-bearing counterpart to all of them, see the crushed stone calculator.
Frequently Asked Questions
What size is #57 stone?
#57 is a washed, open-graded crushed stone running from about 1/2 inch to 1 inch, with most pieces around 3/4 inch. The number comes from the ASTM/AASHTO gradation system, not the stone size itself.
Does #57 stone compact?
Not in the usual sense. Because it is washed clean of fines, #57 interlocks but keeps 36–42% open voids no matter how much you roll it. That makes it superb for drainage and a stable — but never dense — base layer.
What is #57 stone used for?
French drains, foundation and retaining wall backfill, under concrete slabs, permeable paving reservoirs, and as the clean top layer on gravel driveways over a compacted crusher run base.
How much does a yard of #57 stone weigh?
About 1.45 US tons (2,900 lb) per cubic yard — slightly lighter than dense-graded stone because the voids between the washed, uniform pieces hold air instead of fines.