Crushed Stone & Gravel Grades | How To Determine The Correct Size For Your Project?

Crushed stones and gravel are among the most used construction materials in the world. They have versatile applications, from being used as a base material in construction projects to decorating landscapes in home and business settings. If you have previously dealt with gravel and crushed stones, you must know that they come in various grades (sizes). Depending on the distributor and where you live, these sizes will vary.  Learn what s best for You crushed stone and gravel size chart and grades.

However, in most cases, crushed stones are available in more or less uniform sizes within a given grade. Most sellers use a numerical system to assign a size to crushed stones and gravel. Each grade has its own unique applications, and when planning for your next project, you cannot assume that one size fits all.

Crushed Stone & Gravel Grades  How To Determine The Correct Size For Your Project
Pea gravel: a gravel type regularly used for various landscaping projects such as patios, walkways & driveways.

Photo by pxhere

Understanding the difference between various crushed stone and gravel grades is helpful when selecting material for your project. Choosing the right size will help you ensure higher quality and a longer-lasting finished product. Moreover, it will also help you save some money and avoid wastage.

So, if you are planning to buy gravel or crushed stones, read this article. We have covered all the basics to give you a general overview of gravel sizes and grades. Hopefully, this information will be helpful when buying material for your next project.

Gravel Vs. Crushed Stones

Gravel Vs. Crushed Stones
Crushed stone: an artificially-made construction aggregate typically produced in a quarry.

Photo by 攝影師

Before we explain the various sizes and grades of crushed stones and gravel, it is important to understand the difference between them. It will help you choose the right material for your next construction or decoration project.

Difference In Sources

Gravel is the fragmented rock that is sourced from weathered rock deposits in streams, gravel pits, and rivers. In contrast, crushed stones are formed artificially with the help of machines by mining and crushing natural rock.

Difference In Shapes

Gravel has a rounded shape and corners due to natural weathering and erosion. Whereas crushed stone usually has a boxy shape with more angular surfaces.

Difference In Sizes

Gravel usually come in sizes ranging from two millimeters to about a quarter of an inch and going up to three inches or even more. In contrast, crushed stones are available in sizes ranging from fine dust to rocks measuring in feet.

RELATED: Pea Gravel Patio 101: Pros, Cons, Costs, Installation Guide & Much More!

Different Types Of Gravel & Crushed Stones

For most people, stones are, well, just stones. However, crushed stones and gravel are of many types. The following table shows you the most common types of gravel and crushed stones available in most markets.

GravelCrushed Stones
River rock gravelSlate
Pea gravelSandstone
Jersey Shore gravelGranite
Bank run gravelLimestone
Traprock gravelMarble
Crushed stone gravelBasalt
Marble chipsDolomite

Note: Although gravel is a naturally formed product, some suppliers mine gravel in quarries. Examples include marble chips and crushed stone gravel.

Gravel Sizes & Grades

Gravel is measured and graded according to the particle diameter or size. In the United States, the term gravel is also used for crushed stones that are smaller than two inches in size. However, the term crushed stone is never used for gravel.

In this article, when talking about the various sizes and grades of gravel, we will use the US definition, which also encompasses crushed stones. Remember that these sizes may vary from place to place, though they are very similar in most cases.

Each of these sizes also comes in different colors and attracts different prices. So, ensure you know exactly what you need before placing an order. Another thing to remember when ordering is that gravel grades do not tell you about the stone type.

Nevertheless, here are the commonly used gravel sizes and grades.

Crushed Stones #1

Crushed Stones #1 are the largest size of crushed stones and measure between two to four inches in diameter. Because of their immense size, they are not suitable for shoveling purposes, and you will have to work with #1 crushed stones individually.

Typical uses of #1 crushed stones include:

  • Large jobs, such as filling big holes and making culvert ballasts
  • Lining diversion pits of rainwater and drainage ditches
  • Near water bodies to prevent soil erosion or in areas with a high risk of erosion
  • Can also be used to make sub-base for roads and driveways
  • For decorative purposes on lawns, patios, gardens, and homes

Note: Crushed stones #1, when used for making the sub-base of roads or driveways, will need screening gravel. Also, do not use these stones on patios, walkways, and pathways unless you intend to cover them with finer gravel.

Crushed Stones #1 typically costs around $18 to $20 per ton.

Crushed Stones #2

Crushed stones #2 measure between ½ to 2-2/2 inches in diameter. They are obtained through the crushing and compaction of larger stones, followed by screening through a three-inch wide square screen. However, these stones are not really very popular, and most suppliers do not sell them.

Nonetheless, common uses of #2 crushed stones include:

  • Construction of septic tank filter system
  • Constructions of systems for managing stormwater
  • Construction of drywall entrance and exit points
  • Landscaping and decoration
  • Construction of sub-base for structures that need stability like roads and patios
  • Also used for filling holes and making culvert ballast

Crushed Stones #2 normally costs around $15 to $18 per ton.

Crushed Stones #3

Crushed stones #3 measure between 1/2 to 2 inches in diameter. Crushed stones #3 have a broad range of uses and are very popular. Some of the most popular applications and uses of crushed stones #3 include:

  • The construction of a base for septic systems
  • Constructions of dry wells
  • Construction of driveways and walkways bases with screening
  • Construction of drainage systems
  • Applications in more extensive projects such as railroads, roads, and so on.

Crushed Stones #5

The stones in category #5 are smaller than one inch. These stones do not compact easily. Thus, they are ideal for and are extensively used to make paver and road bases.

Crushed Stones #8

Crushed Stones #8 are also known as clean crushed stones, or 3/8-inch washed stones. They are about 3/8 to ½ an inch in diameter. Crushed Stones #8 are considered an aggregate. Following crushing which reduces the size of stones, it is passed through a 3/8-inch square screen. Then the Crushed Stones #8 are cleaned, and the dust is removed.

Common applications of Crushed Stones #8 include:

  • Use in drainage systems
  • Decorative purposes, especially on lawns and gardens
  • Construction of base for horse barns
  • In concrete mixes
  • Constructions of sidewalks and driveways
  • As part of the aggregate in asphalt
  • Construction of sub-base for patios and sidewalks

Crushed Stones #10

Also known as stone dust or gravel screenings, Crushed Stones #10 is the pulverized stone or residue that is produced during the stone crushing and breaking process. These stone screenings are compact very easily, and they are very sturdy. Moreover, they are easy to handle and can be worked by hand.

Common applications of Crushed Stones #10 include:

  • Used in crevices between larger stones as a filling and to prevent movement
  • Extensively used as a base material for making concrete slabs and concrete blocks
  • Because of its sturdiness and reliability used as a final layer in patios
  • Used a base for concrete pavers, patio stones, and clay bricks

Note: Avoid using Crushed Stones #10 ot gravel screenings in muddy places as they mix with the dirt, creating a mess.

Crushed Stones #57

Crushed Stones #57 has rocks that measure about ¾ of an inch. Crushed Stones #57 is used extensively and is very affordable. The product is cubical and is mainly used in projects that need mixes or crush counts. Due to the small size, Crushed Stones #57 are easy to handle and can be manipulated with hands as desired.

Common used of Crushed Stones #57 include:

  • Construction of foundation backfills
  • Construction of bases for paved driveways
  • For making RV pads and walkways
  • For making aggregate for hot-mixed asphalt and concrete mixes
  • Construction of french drains
  • In landscaping
  • For drainage control purposes
  • Topdressing walkways, driveways, and pathways
  • For lining underground pipes and cables
  • For retaining walls

Crushed Stones #57 costs around $50 per ton. They are usually supplied in truckloads, and one truckload contains around 10 to 12 cubic yards of Crushed Stones #57. However, the cost will vary depending on the supplier and where you live.

Moreover, the price will also vary depending on the type of rock used. For instance, crushed limestones are usually cheaper, whereas Quartz Crushed Stones #57 can cost around $100 per ton or even more.

Crushed Stones #67

Crushed Stones #67 are slightly smaller than Crushed Stones #57, measuring less than ¾ of an inch. It is workable by hand and somewhat compactable as well. Common uses of crushed stones #67 include

  • It is used in hot-mix asphalt and pre-mixed concrete
  • It is used to boost drainage around drain pipes
  • It is used as gravel in walkways and driveways
  • It is used as a base material for slabs and roads
  • It is used for filling and backfilling retaining walls
  • It is used to compact hard soil

Crushed Stones #411

Crushed Stones #411 is similar to Crushed Stones #57, with one major difference. Unlike Crushed Stones #57, it has rock screenings or rock dust created during breaking and crushing rock when making  Crushed Stones #411.

The presence of rock dust makes it more compactable than Crushed Stones #57. It is commonly used in places where compaction is needed. Common applications and uses of Crushed Stones #411 include:

  • It is used in compactible fills
  • It is used in paver and wall base
  • It is used in parking lots and places where you need compactable crushed rocks

Gravel Size Categories

All of the above-mentioned stone sizes and grades were for man-made products. However, suppose you are specifically looking for how naturally formed gravel is classified. In that case, there are two ways of categorizing it.

Udden-Wentworth Scale

According to the Udden-Wentworth scale, gravel can be divided into pebbles ranging in size from 4 mm to 64 mm (0.2 to 2.5 inches) or granules with particles ranging from 2 mm to 4 mm (0.079 to 0.157 inches). Subcategories of granular gravel are fine and very fine. In contrast, medium, coarse, and very coarse are the subcategories of pebble gravel.

Lastly, boulders and unlithified cobblestones (existing as separate pieces and not sedimented together) are regarded as gravel by the Udden-Wentworth scale. Boulders are larger than 256 mm, and cobblestones are between 64 mm and 256 mm (2.5 to 10.1 inches) in size.

International Organization for Standardization ISO 14688

As defined by ISO 14688, gravel is any rock fragment that is larger than 2 mm and less than 63 mm in size. Additionally, ISO 14688 divides them into three categories—fine, medium, and rough.

  • Particles in fine gravel are larger than 2 mm but smaller than 6.3 mm (>2 mm 6.3 mm).
  • Particles in medium gravel are larger than 6.3 mm but smaller than or equal to 20 mm
  • Particle sizes in coarse gravel are greater than 20 mm but not greater than 63 mm.

As you can see, this classification disregards whether gravel is made of crushed rocks or is a naturally occurring substance. Only the sizes are considered.

Gravel/Crushed Stones Size Chart

GradeSize (inches)
Crushed Stones #12 to 4
Crushed Stones #21/2 to 2-2/2
Crushed Stones #3½ to 2
Crushed Stones #5One or less
Crushed Stones #83/8 to ½
Crushed Stones #101/8 or smaller
Crushed Stones #57About ¾
Crushed Stones #67less than ¾

Conclusion | Gravel/Crushed Stones Sizes & Grades

Always read the vendor’s description before purchasing any gravel or crushed stones. Also, always double-check and ensure that your vendor is using the identical chart that we provided above. Lastly, ensure you explicitly ask the dealers what sizes they are selling since different sizes have varied applications.

Frequently Asked Questions (FAQs)

What size of gravel is best for a driveway?

Ideally, you should use gravel in the driveway that is neither too large nor too round. Most commonly used gravel types for driveways are about ¼” -1″ in size.

How do you choose gravel size?

Gravel comes in various sizes, and every size has specific uses and applications. For instance, if you want to cover a patio, you must use smaller and finer gravel. However, if you are making a base, you will want larger and coarser gravel.

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Morgan Daniels

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