#57 is clean, open-graded stone — washed, single-sized, fines removed. It drains, it carries load through point contact, and it does not compact the way a base course does. That last property is the whole reason to use it, and the reason it ruins a driveway base.
For French drains, trench and pipe backfill, drainage layers and permeable paving bases. Enter the area and depth, or the trench dimensions.
Works in metric and US imperial — you choose at the start and can switch at any time. Every figure this calculator uses is published with its source, and the result comes with a printable order sheet. No account, no email, and nothing you type leaves your browser.
Related: Crushed stone calculator · Crusher run calculator · Gravel calculator
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Area × depth, or trench length × width × depth, gives the volume in place. The calculator then adds 14% for settlement — not compaction, because clean stone does not compact in the usual sense — and converts to weight at 1,527 kg/m³. Order the loose figure and you finish with the depth you asked for. Do not add anything on top of it; the allowance is already applied.
A French drain 10 m long, 300 mm wide and 400 mm deep is 1.2 m³ of stone in place. With settlement that is about 1.37 m³ to order, weighing roughly 2.1 tonnes. That is a small tipper load, and it will barrow easily — but there is still around two tonnes to a cubic yard, so check the tipping point has headroom and firm ground before it arrives.
Most aggregate densities on any calculator are trade convention. These are not. They come from an FHWA study of open-graded aggregates, which measured #57 at a minimum dry unit weight of 95.4 lb/cu ft and a maximum of 108.7 — about 14% between loosest and densest, against roughly 25% for dense-graded stone. That measured range is where the settlement allowance comes from, and it is the best-grounded figure we publish.
French drains, trench and pipe backfill, drainage layers and permeable paving bases. It is clean, open-graded stone: washed, single-sized, fines removed. It drains freely and carries load through point contact between stones.
In practice, yes. Both are 3/4 in nominal clean stone and the sieve envelopes differ only slightly at the coarse end. Yards often carry one or the other and treat them as interchangeable, so order whichever your supplier stocks.
Not the way a base course does, and that is the point of it. The voids between stones stay open, which is what makes it drain. If something needs to sit level on top, clean stone cannot be screeded flat and held — you need a dense-graded base or a bedding layer instead.
Yes. Wrap it, or it silts up. The stone works because the voids stay open, and fine soil migrating in from the sides fills them. A drain that has silted cannot be cleaned out — it has to be dug up and rebuilt.