Sandpaper is an incredibly useful tool that has been around for centuries. The oldest versions of this type of abrasive coated material discovered have been found in China, dating back to the 13th century when Genghis Khan roamed the region. Unlike modern-day sandpaper, early versions used actual sand. Sand and crushed up seashells were bonded to parchment paper to form a crude, but effective abrasive.

Modern-day sandpaper and abrasives are much more advanced. The sand has been traded in for stronger natural and man-made materials and more precise sized grains, also known as the grit sizes.

Understanding sandpaper grit is a requirement when you want to get a perfect finish on your project. Whether you're working on wood, metal, or any other material, choosing the right grit can make all the difference. In this guide, we'll break down everything you need to know about sandpaper grit, including how it's measured, the different types of grit, and how to choose the right one for your needs.

Grit Sizes Explained

What is Sandpaper Grit?

Sandpaper grit refers to the size of the abrasive grains on the sandpaper. These grains are responsible for sanding down surfaces. The grit size is indicated by specific numbers. The lower the number, the coarser the grit. The higher the number, the finer the grit. For example, 40 grit sandpaper is much coarser than 400 grit sandpaper.

How is Sandpaper Grit Measured?

The grit of sandpaper is measured by counting the number of abrasive grains per square inch. In order to get a uniform grit size across the surface of your sandpaper, the materials being used go through a sifting machine. The filters on this machine will only allow specific sized particles of the materials to pass through each level.

The size of the grit is then determined by how many of each particle can fit through a 1 square inch filter. The larger the particle, the less can fit through at once.

So let’s say we have a sandpaper with a grit size of 30, that means 30 particles would fit through the filter. A grit size of 100 would mean that much more particles would filter through with much smaller particles.

Another way to visualize this is to picture a basketball hoop. Imagine dropping a pile of golf balls through the hoop. The balls are small so you’ll be able to fit a lot, let’s make believe 100, so we’ll give the golf balls a 100 grit. Now do the same process with softballs. They are much bigger than the golf balls, so less will fit at once, let’s say 20. That would be a coarser particle with a grit of 20.

Grit sizes will range in appearance from being fine enough to resemble the size of aby powder all the way up to larger grits the size of Kosher salt.

Systems for Measuring Sandpaper Grit

There are two commonly used numbers you will see correlated with grit sizing- CAMI and FEPA. The United States uses CAMI - Coated Abrasive Manufacturers Institute. Europeans use FEPA - Federation of European Producers of Abrasives. The numbers are fairly close for larger grit sizes but differ more with smaller grits.

There are also several other grading systems you may rarely see including the Japanese Industrial Standards Committee (JIS), micron grade, and the aught system.

Sandpaper Materials/Grains

Different materials are currently used to create various types of sandpapers. Each of these materials has unique properties allowing each to provide targeted results on varying surfaces. Here is a quick overview on these abrasive grains, since the grains are what is measured for the grit size.

Natural Abrasive Materials

• Garnet - A common choice for hand sanding, especially when working with wood to remove light scratches and prepare surfaces for finishing. Garnet sandpaper tends to wear quickly, which can be beneficial as it provides a finer finish as it wears down.
• Emery - Also known as emery cloth due to its cloth backing, emery is a coarser abrasive best suited for sanding and polishing metal surfaces.

Man-Made Abrasive Materials

• Aluminum oxide - Useful on most surfaces including wood, metal, plastic, and drywall. A major benefit of aluminum oxide coatings is that as it breaks down, the surface will expose new, sharp edges making this a longer-lasting abrasive.
• Silicon carbide - A popular choice for wet sanding, as silicon carbide abrasives are often made with a waterproof backing. The materials in this sandpaper are capable of removing material faster than aluminum oxide but is not as long-lasting.
• Zirconia alumina - This type of sandpaper is made from an aluminum oxide–zirconium oxide alloy that, like garnet and aluminum oxide, has particles that break down to keep a sharp surface. Zirconia lasts longer than aluminum oxide, but not as long as ceramic. This abrasive is commonly used on wood, fiberglass, and metal surfaces.
• Ceramic alumina - These abrasives are extremely hard and durable, making them an excellent choice for power sanding using ceramic belts or discs. Ceramic abrasives can last up to 6 times longer than other good quality sandpapers.

Uses for Different Grit Sizes

Grit sizes vary so the users can accomplish specific tasks. Different grit sizes are also useful for varying surface types, i.e. wood or metal.

Higher grit numbers (finer with smaller particles) are used for smoothing wood and painted surfaces between coats.

Lower number grit (coarser with larger particles) are generally used on tougher surfaces for heavy sanding, stripping, or cutting hard surfaces.

Oftentimes if you are trying to get a very smooth surface, it would make sense to “go through the grits.” This means you would start with a coarser grit slowly working your way down to finer and finer grits to create an even and smoother surface.

Here's a breakdown of the different grit levels and their common applications:

• Coarse Grits (40 to 60): Used for heavy material removal and shaping wood or metal. Use coarse grit when you need to quickly remove paint, rust, or rough edges. They work well for initial sanding and preparing rough surfaces for further refinement.
• Medium Grits (80 to 120): This is a versatile grit range, perfect for general sanding tasks. Medium grits smooth surfaces after using coarse grit and prepare them for finer sanding. They are also effective for removing light surface imperfections.
• Fine Grits (150 to 180): Use fine grit for final sanding before finishing. It smooths surfaces and prepares them for painting or staining.
• Very Fine Grits (220 to 240): Excellent for polishing and fine finishing work. This grit level is often used between coats of paint or finish to ensure a smooth, even surface.
• Extra Fine Grits (320 to 400): Ideal for ultra-smooth finishes and polishing tasks. This grit is commonly used in automotive work or for polishing metal and plastic surfaces.
• Super Fine Grits (500 to 600): These grits are used for polishing finishes on wood and metal, as well as polishing bare metal surfaces. They often come on waterproof sheets for wet sanding.

Ultra Fine Grits (800 and above): These extremely fine grits are used for the finest polishing and buffing jobs, especially when trying to get a mirror finish. They are commonly used in jewelry making, optical finishing, and other specialized application.

Sandpaper Grit Chart

For our stainless steel grit chart, click here.

Sandpaper Grit FAQ

What is the best grit sandpaper for wood?

For most woodworking projects, start with 80 grit for rough sanding and finish with 150-180 grit for smoothing before staining or painting. If your goal is an ultra-smooth finish, progressing to 220 grit or even higher may be necessary before applying a final finish

How do I choose the right grit for metalwork?

Begin with a coarse grit (40-60) for removing rust or paint, then switch to a medium grit (80-120) for smoothing. Finish with a fine grit (220 or higher) if you're polishing the metal.

Can I reuse sandpaper?

Yes, but it depends on the condition of the sandpaper. If the grit has worn down or the paper is clogged, it's time to replace it. Cleaning the sandpaper with a brush or compressed air can often help extend its lifespan

What are the 3 grades of sandpaper?

Technically, they are (40 to 60 grit), Medium (80 to 120 grit), and Fine (150 to 220 grit). Coarse and fine can also be broken down into other levels such as extra coarse, super fine, and ultra fine.

What is the finest grit sandpaper?

The finest grit sandpaper typically ranges from 2000 to 3000 or even higher, used for ultra-fine polishing and achieving a mirror-like finish on surfaces like metal, glass, and certain plastics. Anything over 2000 grit sandpaper is often made with specialized materials like micro-mesh or diamond polishing compounds instead of traditional sandpaper materials.

What is the lowest grit sandpaper?

The lowest grit sandpaper commonly available is 24 grit, which is extremely coarse and used for heavy material removal and rough shaping of surfaces. Some manufacturers produce even coarser grits like 12 or 16, primarily used for industrial applications

Choosing the Right Grit Size

Of the many properties of sandpaper abrasives, grit size is just a piece of the puzzle for picking the right tool for the job. Hopefully, this guide helped you figure out the right grit size for your job. If you still have questions or comments, please feel free to reach out to one of our experts at Empire Abrasives, 1-800-816-3824.

Visit our Sandpaper products page to find the perfect grit for your needs.