The standard gravel size can vary depending on its intended use and regional standards. Gravel is generally categorized into different sizes based on the diameter of the individual stones.
Table of Content
- Gravel Size Chart
- Most common types of gravel compared
- How to Choose the Right Gravel Size
- What are the Types of Gravel?
- Frequently Asked Questions
Gravel Size Chart
Gravel and crushed stone size chart
| Gravel number | Size in inches | Size in mm |
| #1 | 2 – 4 inches | 50.0 -102 mm |
| #2 | 0.5 – 2.5 inches | 13.0 – 63.5 mm |
| #3 | 0.5 – 2.0 inches | 13.0 – 50.0 mm |
| #4 | 1.0 – 2.5 inches | 25.0 – 63.5 mm |
| #5 | 1.0 inch | 25.0 mm |
| #8 | 0.4 – 0.5 inches | 10.0 – 13.0 mm |
| #10 | 0.1 inches | 3.0 mm |
| #57 | 0.8 inches | 20.0 mm |
| #67 | less than 0.8 inches | Less than 20.0 mm |
Most common used gravel compared in a table
Find below the Comparison Table of the most popular gravel types and sizes, how they look and what they are used for. Some types of gravel come in a variety of sizes and a variety of colors.
| Type of Gravel | Characteristics | Best Uses | Edging Required? |
|---|---|---|---|
| Pea Gravel | Small, rounded stones in natural colors | Walkways, driveways’ top layer | Yes |
| River Rock | Smooth and rounded gravel in natural shades | Landscaping, top layer of driveways | Yes |
| Lava Rock | Porous structure, comes in red, black, or gray | Weed control, mulch, and aesthetic landscaping | No |
| Marble Chips | Chipped marble in white and gray | Walkways, driveways’ top layer | Yes |
| Jersey Shore Gravel | Small, smooth gravel in golden color | Driveways, walks, landscaping in specific regions | Yes |
Note: Edging is recommended to prevent displacement of smooth gravel types like pea gravel, river rock, and marble chips.
How to Choose the Right Gravel Size
Gravel sizes are based on the diameter in inches of the stones. Its size often determines its use and what it is called – pea gravel, river gravel, washed gravel, and river rock of various sizes. However, the correct size of gravel you need will depend on the application. This section will discuss the best use for the various stone grades.
#1 Gravel
This gravel size is the largest, featuring stones with a diameter of 2-4 inches (50 – 102 mm). Since they are large, it’ll be hard to shovel them, and you’ll have to place them one at a time. The common applications for this gravel grade include:
- Making ballast
- Filling larger holes
- Reducing soil erosion
- Lining ditches
- As a decorative stone collection for gardens, patios, and yards
You can also use these rocks as the foundation for roads, driveways, and walkways but you’ll have to topdress them with stone dust. They can be unstable to walk on because of their size and require finer gravel for added stability.
#2 Gravel
This gravel size is rare, and you won’t easily find it on the market. The rocks have a diameter of 0.5 – 2.5 inches (13 – 63.5 mm). Here are the common ways these crushed rocks are used:
- Making ballast
- Filling holes
- Landscaping, and decoration
- Septic tank filtration
#3 Gravel
Perhaps the most popular gravel size for home projects, #3 gravel has a diameter of 0.5 – 2 inches (13 – 50 mm). You can use them for:
- Residential drainage projects
- Making ballast
- As a road base
- On driveways
- Filling dry wells
- As a base in septic filtration systems
Using them in your driveway should also include stone screenings to ensure the ground is stable enough for movement.
#4 Gravel
This gravel is about the size of a golf ball or an egg. It measures 1 – 2.5 inches (25 – 63.5 mm) in diameter and usually comes from crushed concrete. It can be a decoration or base for walkways when topdressed with fine gravel.
#5 Gravel
You need this if you are looking for the ideal particle size range to fill crevices and the spaces between larger stones. The gravel measures about an inch in diameter and is ideal for driveways, walkways, and roads.
#8 Gravel or Coarse sand
These crushed stones measure between 0.4 and 0.5 inches (10 – 13 mm). Mostly, these stones go through cleaning to eliminate dust and residue, giving them a smoother appearance. Some common applications include:
- Making asphalt
- Creating concrete mixes during construction
- As a subbase in patios, walkways, and driveways
- As decoration around vegetation
- As a base in horse barns
- To assist in drainage
#10 Gravel
Also known as stone dust, gravel screenings, or rock screenings, #10 gravel is a by-product of the stone-breaking process. They are compact and easy to apply, making them suitable for the following:
- As a paving base in stones, bricks, and concrete
- Making concrete slabs and blocks
- Filling spaces between larger rocks for stability
- Top-dressing driveways and sidewalks
Screenings can quickly get dirty, so you shouldn’t use them in muddy places.
#57 Gravel
This middle-range gravel size is easy to find and suitable for different functions. It measures about 0.75 inches (20 mm) and is ideal for any of the following uses:
- Making hot-mix asphalt
- RV parking pads
- Driveways and parking lots
- Landscaping purposes
- Topdressing on a sub base
- Making railroad ballast
- Helping drainage
- Lining underground paths for pipes and cables
My Pro tip: Use Jagged edge gravel for Driveways: Gravel with jagged edges may provide better interlocking and stability when used as a base material for driveways or pathways, as the irregular shapes can help create a firmer surface.
#67 Gravel
This gravel size is smaller than 0.75 inches (20 mm) and is among the smallest options. You can use it for:
- Making concrete blocks and slabs
- As a base on roads
- Improving drainage around water systems
- Stabilizing larger rocks
- Retaining walls
What are the Types of Gravel?
Gravel comes in different forms. Let’s look at the various types of gravel you can buy.
1. Bank Gravel
You can find this type of gravel naturally occurring in rivers and streams. It could be mixed up with the sand or natural soils on the river bank. Bank gravel is usually smooth and round and has an aesthetic look.
2. Bench Gravel
You’ll find bench gravel near valleys where streams flow by. It’ll indicate that the water levels are reducing, allowing the gravel to be visible instead of inside the stream.
3. Crushed Stone
Unlike natural gravel, crushed stone is a by-product of the quarry process and is mostly used to surface roads and driveways. Crushed stone isn’t smooth; instead, it’s edgy and coarse.
4. Fine Gravel
This is gravel with a very small diameter. It’s often used to stabilize the spaces between huge stones and road bases.
Pro tip: A common fine gravel type for French drains is “drainage gravel” or “drain rock.” The recommended size for drainage gravel in a French drain system is usually between 1/4 inch to 3/4 inch (about 0.6 cm to 1.9 cm) in diameter.
5. Stone Dust
As crushed stone goes through screens, the smallest are mixed with fine dust particles.
6. Pay Gravel
This gravel type comes with a lot of precious metals like gold. Miners can extract the gold using a method called gold panning.
7. Pea Gravel
Pea gravel gets its name from its size and appearance. The gravel looks clean and about the size of a pea.
Gravel and crushed stone sizing systems explained
ISO 14688-1 gravel size categories
ISO 14688-1 is the international standard for identifying and classifying soil, including gravel, by particle size. It splits gravel into three groups:
- Coarse gravel: 20 mm to 63 mm
- Medium gravel: 6.3 mm to 20 mm
- Fine gravel: 2 mm to 6.3 mm
Udden-Wentworth Scale Gravel Size Categories:
The Udden-Wentworth scale, also known as the Wentworth scale, is a widely used logarithmic scale for classifying sediment particle sizes, including gravel. It categorizes particles based on their diameters. The gravel size categories in the Udden-Wentworth scale system are as follows:
- Granule: 2 mm to 4 mm – Grains in this category fall between the sizes of sand and pebbles.
- Pebble: 4 mm to 64 mm – Pebbles are larger than granules but smaller than cobbles.
- Cobble: 64 mm to 256 mm – Cobbles are larger than pebbles but smaller than boulders.
- Boulder: Greater than 256 mm – Boulders are the largest category, with particles having diameters greater than 256 millimeters.
Frequently Asked Questions
1. What size is #1 gravel?
#1 gravel has a diameter of 2 – 4 inches (50 – 100 mm).
2. What size gravel is best?
The answer depends on your situation. Selecting the appropriate size of crushed stone and gravel is crucial to the success of any construction or landscaping project. The size determines the stone’s load-bearing capabilities, drainage properties, and aesthetics. The application you want will determine the right size of gravel to use.
3. What size is #4 gravel?
#4 gravel measures about 1 – 2.5 inches in diameter (25 – 63.5 mm).
4. What size of gravel is best for a driveway?
#3 Gravel is the best size for driveways since it provides a stable platform and proper drainage thanks to its medium-sized diameter.
5. What is 10mm gravel used for?
10mm gravel or #8 gravel is great for decorative purposes in your landscape. It adds interest, paves walkways, and suppresses weed growth.
6. What area will 1 ton of gravel cover?
It depends on the gravel size. A ton of 0.3 – 0.5 inch gravel will approximately cover about 100 sq. ft at a depth of 2 inches.