A 57 stone calculator needs to account for something most general stone calculators gloss over: #57 is an open graded material meaning it's made of uniformly sized pieces with a lot of space between them rather than a tightly packed mix.
That structure changes both how much you order & how you install it. This guide covers what #57 actually is how to work out the quantity you need & one detail that trips up a lot of first time buyers: compacting this stone the wrong way can undo the exact drainage performance you bought it for.
For the general area & depth formula behind any stone order our crushed stone calculator covers that step in full our gravel calculator works the same way if you're ordering a gravel mix instead of pure stone or start with our broader stone calculator if you're comparing #57 against other stone types.
Key Takeaways
#57 Stone Is A Size Classification
#57 is a size designation not a measurement in inches. The stone itself typically ranges from 3/8 inch up to 1 inch with most pieces landing around 3/4 inch. The number comes from a standard aggregate gradation system.
#57 Stone Has Lower Density Due To Open Structure
Being open graded changes its weight per cubic yard. Because #57 has more void space than a denser blended material its density often runs a bit lower than tightly packed crushed stone typically somewhere around 1.2 to 1.5 tons per cubic yard.
Compaction Depends On The Project Type
Compaction depends entirely on the use. Drainage applications generally should not be heavily compacted since that closes the gaps water needs to move through. Structural uses benefit from light compaction only.
Common Uses Of #57 Stone
#57 stone is used for many projects including French drains under slab drainage retaining wall backfill & driveway topping. The installation method changes depending on the project requirements.
What Is #57 Stone?
Number 57 is a crushed stone aggregate usually made from limestone granite or trap rock that has been crushed & screened to a specific size range. Most pieces fall around 3/4 inch with the full range running from about 3/8 inch up to a nominal top size of 1 inch.
The "57" itself comes from a standard aggregate gradation system used across the construction industry not a literal inch measurement. Because the pieces are angular rather than rounded they interlock loosely with each other while still leaving open space between them which is exactly what makes this stone useful for drainage.
It is useful to know that #57 sits in a family of related gradation numbers. #67 is a slightly finer more tightly graded version that packs into a denser surface while #8 is finer still & often used as a concrete mix component or a finishing layer rather than a drainage material. If #57 does not match your project needs it is worth checking whether another grade fits better before ordering.
How Much Does #57 Stone Weigh?
Weight per cubic yard is where #57 differs from some other crushed stone products. Since it is open graded meaning it is made up of one consistent size range with no sand or fine particles mixed in there is more air space between the pieces than in a denser blended material.
That void space means #57 often runs a bit lighter per cubic yard than tightly packed base materials. A reasonable planning range is about 1.2 to 1.5 tons per cubic yard though your supplier's figure based on their exact source rock & moisture content will always be more accurate than a general range.
Calculating Your #57 Stone Quantity
The volume math for #57 stone follows the same steps as any other crushed stone. Multiply length by width by depth all in feet to get cubic feet then divide by 27 to get cubic yards. Multiply that figure by your chosen density to get tons.
Worked Example
Say you're building a French drain trench that is 30 feet long 1.5 feet wide & 1.5 feet deep. That works out to 67.5 cubic feet or about 2.5 cubic yards. At 1.3 tons per cubic yard that comes to roughly 3.25 tons before any waste allowance.
Where #57 Stone Works Best
This stone is used across a wide range of projects because its open structure serves two important purposes: allowing water to pass through & providing a stable interlocking base.
French Drains & Drainage Trenches
The open structure allows water to move freely around a perforated pipe which makes #57 stone a common choice for French drains & other drainage systems.
Under Slab Drainage
#57 stone is placed beneath concrete slabs to reduce moisture buildup & create a stable drainage layer before concrete installation.
Retaining Wall Backfill
This stone helps move water away from retaining wall structures while providing support behind the wall.
Driveway Topping & Base Layers
#57 stone can be used for driveway surfaces & base layers because it settles enough to create stability while still allowing water drainage.
General Site Drainage
It is useful in areas where excess water needs a pathway to drain instead of collecting on the surface. If your project also includes garden beds or borders that require a mulch layer the mulch calculator handles that part of planning using the same length width & depth approach.
Compaction: What Not To Do With #57 Stone?
This is where many #57 stone orders go wrong after delivery rather than before it. For pure drainage applications such as French drains or under slab drainage layers you generally should not compact the stone.
Compaction pushes the angular pieces closer together which closes the void spaces that allow water to flow through. For structural uses like a driveway base light compaction with a plate compactor is suitable because it helps the stones interlock & settle without removing all the open space. A heavy vibratory roller is different.
Excessive force can crush the angular pieces breaking down the aggregate & reducing the drainage performance that makes #57 stone valuable. If you are unsure which category your project falls into ask your supplier or contractor before compacting because fixing the mistake usually requires removing the stone & starting again.
It is also important to consider timing. Compaction decisions are easier to manage before installation rather than after the stone has been placed. Confirm whether your project is focused on drainage or structural support while ordering the material instead of deciding after delivery.
Conclusion
A 57 stone calculator needs to consider more than just area & depth because the open graded structure affects both weight & installation methods.
Calculating the correct quantity is only one part of the process. Using the right compaction method determines whether the stone performs properly for drainage or structural purposes.
FAQs
How Many Tons Of #57 Stone Are In A Cubic Yard?
A cubic yard of #57 stone usually weighs around 1.2 to 1.5 tons. The exact weight depends on the source rock moisture level & how the stone has settled. For large orders it is best to confirm the exact density with your supplier.
Should I Compact #57 Stone For A French Drain?
No. #57 stone used for drainage should generally not be compacted. Compaction reduces the open spaces between the stones which limits water movement through the material.
What Size Is #57 Stone Exactly?
#57 stone usually ranges from 3/8 inch up to a nominal top size of 1 inch. Most pieces are around 3/4 inch. The number refers to a standard gradation classification rather than an exact measurement.
Can #57 Stone Be Used Under A Concrete Slab?
Yes. #57 stone is commonly used as an under slab drainage layer. Unlike open drainage trenches it is usually compacted to create a firm stable base before concrete placement.
Is #57 Stone Good For A Driveway?
Yes. #57 stone works well for driveway base layers & topping because it creates a stable surface while still allowing water to drain which helps reduce standing water & erosion.