What Does Grit Mean On Sandpaper? Numbers, Grades, Uses

Every abrasive product on the shelf has a number printed on it, and that number controls the outcome of your work more than most people realize. So what does grit mean on sandpaper, exactly? It refers to the size of the abrasive particles bonded to the backing material, and it directly determines how much material gets removed with each pass.

The grit number follows a standardized scale. Lower numbers like 40 or 60 indicate larger, more aggressive particles that cut fast and leave deep scratches. Higher numbers like 400 or 800 mean smaller particles that produce a smoother, more refined finish. Picking the wrong grit doesn’t just slow you down, it can damage a surface or leave marks that take real effort to fix.

At DeFusco Industrial Supply, we stock a full range of abrasives built for stone, tile, and masonry professionals, people who can’t afford guesswork when it comes to surface prep and finishing. This article breaks down how the grit numbering system works, what separates coarse grades from fine, and how to match the right grit to your specific application so you get clean results without wasted time or material.

Why grit matters for speed and finish quality

Grit is the single variable that controls how fast you remove material and what the surface looks like when you’re done. Choose a grit that’s too coarse for the job and you’ll tear into the surface, leaving scratches deep enough that you need several more sanding stages to correct them. Choose one that’s too fine and you’ll spend far more time than necessary without making any real progress on a rough surface.

The grit you start with sets the ceiling for every step that follows, so getting it wrong at the beginning costs you time at every stage.

How coarse grits cut faster but leave deeper marks

Coarse grits, typically in the 40 to 80 range, use larger abrasive particles that bite aggressively into the surface. This makes them ideal for heavy stock removal, such as stripping old coatings, flattening uneven slabs, or grinding down high spots on stone or concrete. The trade-off is that these particles leave visible scratches in the surface profile, which you’ll need to address with finer grits in subsequent passes.

When you’re working with stone or masonry, coarse grits handle the bulk of the structural work. A diamond grinding cup or coarse abrasive pad on a concrete floor, for example, removes the top layer efficiently, but you wouldn’t stop there if you need a smooth finish. Each step down to a finer grit is essentially erasing the scratch pattern left by the previous one.

How fine grits refine and polish without cutting deep

Fine grits, generally 220 and above, use much smaller particles that produce less aggressive cutting action. Instead of tearing into the surface, they refine it, gradually reducing the scratch pattern until the surface looks and feels smooth. For stone professionals, polishing pads in the 400 to 3000+ range are what take a honed surface to a high-gloss finish.

Understanding what does grit mean on sandpaper also means recognizing that fine grits aren’t faster, they’re more precise. If you jump straight to a fine grit on a rough or damaged surface, the particles are too small to remove the irregularities efficiently. Your work time goes up without the result improving. The correct approach is always to start coarse enough to cut efficiently, then work your way up through progressively finer grits to reach the finish quality your project demands.

How grit numbers work and what P means

When you look at a piece of sandpaper, the grit number printed on the back tells you the size of the abrasive particles relative to a standardized scale. Two main grading systems define what does grit mean on sandpaper in practice: CAMI (Coated Abrasive Manufacturers Institute), which is the standard used in North America, and the FEPA P-grade system, which is common in Europe and increasingly found on professional abrasives worldwide.

The CAMI grading system

The CAMI scale assigns numbers based on how many abrasive particles fit through a mesh screen per square inch. A low number like 36 or 40 means fewer, larger particles pass through, producing an aggressive cut. A higher number means a finer mesh, smaller particles, and a smoother result. Most sandpaper sold in North American hardware stores uses this scale without any prefix, so a label reading "80" or "120" follows CAMI standards.

What the P-grade means on your abrasives

Your P-grade abrasives carry a prefix before the number, such as P80 or P220, indicating the product follows the FEPA standard, which uses a more precise measurement method for particle size distribution. For grits below P220, the CAMI and FEPA numbers are close but not identical, so mixing the two systems on the same project can produce an uneven scratch pattern between sanding steps.

When you work with stone or masonry abrasives, always confirm that your products follow the same grading standard so your progression from coarse to fine stays consistent.

For grits above P220, the two systems diverge more significantly, and the P-grade numbers become larger than their CAMI equivalents. Knowing this distinction helps you build a sanding sequence that actually delivers the surface quality your project requires.

Common sandpaper grit ranges and uses

Understanding what does grit mean on sandpaper becomes practical when you map each range to a real task. Grits fall into four general categories: coarse, medium, fine, and ultra-fine. Each category serves a distinct purpose, and knowing where each fits helps you build an efficient sanding sequence from start to finish.

Coarse and medium grits for stock removal and shaping

Coarse grits (40-80) handle the heaviest work, including grinding down uneven concrete, removing old adhesive from stone slabs, or flattening a rough surface before any finishing begins. Medium grits (100-150) follow coarse work to reduce the deep scratch pattern left behind, blending the surface and preparing it for finer stages without removing excessive material.

Jumping from a coarse grit to a fine grit without working through a medium stage leaves scratch marks that take far longer to remove than if you had stayed in sequence.

These two ranges are where most of the structural surface prep happens. For stone and masonry work, a diamond abrasive pad in the 50-120 range is typically what you reach for when flattening or reshaping a slab before transitioning to polishing stages.

Fine and ultra-fine grits for finishing and polishing

Fine grits (180-400) refine the surface by removing the scratch pattern left by medium grits and producing a smooth, consistent texture ready for sealing or coating. For countertop fabricators and tile installers, this range bridges the gap between prep work and a polished result.

Ultra-fine grits (600 and above) produce the smoothest finishes, and in stone work, these correspond to polishing pads that bring out a high-gloss surface. At this stage, you’re no longer removing material in any meaningful quantity, you’re working at a microscopic level to achieve the final appearance your project requires.

How to pick the right grit for your project

Knowing what does grit mean on sandpaper only gets you so far. The practical skill is applying that knowledge to your specific project. Two factors drive every grit selection: the current condition of the surface you’re working on, and the final finish level your project requires. Get those two right and your sanding sequence almost builds itself.

Start with the condition of your surface

If the surface is rough, uneven, or coated with old material, start with a coarse grit in the 40-80 range to handle the bulk of the removal work first. A surface that’s already smooth and just needs refinement before sealing can start at 100 or 120 without the extra coarse stages.

Never start with a finer grit than the surface condition calls for. It wastes time and burns through abrasive material faster than necessary.

From your starting point, move up by no more than one grit range at a time, such as 80 to 120 then 120 to 180. Each stage removes only the scratch pattern from the previous one, which keeps your surface quality consistent and prevents you from chasing problems created by skipping steps.

Match your grit to the material hardness

Harder materials like granite, quartzite, or porcelain tile need abrasives that stay sharp under pressure, which is why diamond-bonded pads are standard for stone and masonry work. Softer materials like limestone or travertine reach a refined surface at lower grits, so your finishing sequence can stop earlier without sacrificing the result.

Always set your target finish level before you pick up any abrasive. A floor slab getting a sealer needs a different endpoint grit than a countertop getting a mirror polish. Decide where you’re going first, then build your grit progression backward from that goal.

Sandpaper types, coatings, and pro sanding tips

Understanding what does grit mean on sandpaper gives you the foundation, but the abrasive material itself and the backing type affect how that grit performs in real conditions. Not all sandpaper is made the same, and choosing the wrong type for your material can wear out your abrasive faster or produce an uneven finish.

Common abrasive materials and backings

The four most common abrasive materials are aluminum oxide, silicon carbide, garnet, and ceramic. Silicon carbide is harder and works better on stone, glass, and masonry, especially in wet sanding applications, while aluminum oxide handles wood and metal effectively because it’s durable and self-sharpening under pressure. Ceramic abrasives cut aggressively and last longer under high-pressure conditions, making them a solid choice for heavy stock removal on hard surfaces.

Backing materials range from paper, cloth, foam, and film. Paper backs are common for hand sanding and light machine work. Cloth-backed abrasives handle more aggressive applications and resist tearing under pressure, which makes them standard for belt sanders and angle grinders. Film backings offer the most consistent thickness, which translates to a more uniform finish on flat surfaces.

Matching your abrasive material and backing to the surface hardness reduces premature wear and keeps your finish quality consistent across the full sanding sequence.

Pro tips for consistent sanding results

Always keep your abrasive flat and moving during use. Dwelling in one spot, especially with power tools, generates heat that can glaze the abrasive or damage the surface underneath.

Replace your abrasive when it stops cutting efficiently rather than pushing it further. A worn abrasive creates uneven scratch patterns that require additional passes to correct, which costs more time and material than simply swapping it out when performance drops.

Final takeaways

Understanding what does grit mean on sandpaper comes down to one core principle: the number tells you the particle size, and the particle size controls both your cutting speed and your final surface quality. Coarse grits remove material fast but leave deep scratches. Fine grits refine the surface but can’t do the work of a coarse stage. Your sanding sequence has to match both your starting surface condition and your target finish level, or you’ll spend more time correcting mistakes than making progress.

For stone, tile, and masonry work, choosing the right abrasive matters even more because these materials are hard and unforgiving. Skipping grit stages or using the wrong abrasive type leads to results that are harder to fix than they are to prevent. Whether you need diamond polishing pads, grinding cups, or general-purpose abrasives, DeFusco Industrial Supply carries professional-grade products built for the demands of fabricators, installers, and contractors who need reliable results on every job.