Sandpaper is one of the most-used abrasives in home repair, yet the grit number printed on the back of every sheet confuses many DIYers. Grit describes the size of the abrasive particles: lower numbers mean coarser paper, higher numbers mean finer. The right choice depends on the material being sanded and the finish you are working toward. The same matching logic applies across construction, whether you are choosing the right earthmoving equipment for a site or picking sandpaper for a cabinet door.
What Sandpaper Grit Means
Sandpaper grit is sized by a gauge number, with lower numbers signifying larger, coarser grains. A #24 or #40 grit is very coarse and rough, while #1,000 grit is extremely fine with very small particles. The grit number is almost always printed clearly on the back of the paper, and it is the first thing to check when you reach for a sheet.
How grit numbers are made
The number does not count particles per square inch. It refers to the screen used during manufacturing: abrasive grains are sieved through a screen with a set number of holes per square inch. Sixty-grit paper uses grains that passed through a screen with 60 holes per square inch, which is why the scale stays consistent across brands.
The full grit scale
Grit numbers run from #24 up to #1,000, although most people never use the extremes. Grouping grits into coarse, medium, and fine bands makes selection easier, just as a construction tools selection guide groups equipment by the task it performs. Each band removes material at a different rate and leaves a different scratch pattern, so the bands define the sanding sequence from rough shaping to final polish.
Open-coat and closed-coat paper
Beyond the grit number, the construction of the paper matters. Open-coat paper spaces the grains farther apart so sawdust and paint dust do not clog it, which suits paint prep and drywall work. Closed-coat paper packs the grains tightly for maximum cut on bare wood. Backing choices range from flexible paper for hand sanding to cloth for belts and stiff film for discs.
Grit Categories and What Each Does
Coarse grits: 24 to 60
Coarse grits strip paint, level rough lumber, and remove deep scratches. They cut fast but leave visible marks that finer grits must erase, so they belong early in a project. Use them for heavy stock removal and stop as soon as the surface is flat.
Medium grits: 80 to 150
Medium grits do the bulk of everyday sanding. An 80-grit pass smooths wood after coarse work, 100 to 120 grit prepares bare wood for stain, and 150 grit refines surfaces before primer. This band is where most DIY projects spend their time, and it is the range worth buying in quantity.
Fine and superfine grits: 180 to 1000
Fine grits remove the marks left by medium paper and prepare surfaces for finish. Superfine grits above 400 produce the smooth, polished surface used between finish coats and for wet sanding. Selecting among them follows the same logic as any product match: you pick the option that fits the conditions, the way you would when choosing the right fertilizer depends on soil test results and the grass variety.
Wet sanding with superfine grits
Wet sanding uses waterproof paper above 400 grit with water or mineral spirits as a lubricant. The liquid carries away debris and stops the paper from clogging, which is how automotive and fine furniture finishes get their smooth feel. Dry sanding at these grits generates dust that settles into the finish, so wet methods win for final coats.
Quick checks before you start sanding:
- If the surface has deep gouges or old paint, start at 60 grit or coarser.
- If you are only scuffing for a new coat, start at 120 to 150 grit.
- If the final coat must be glass-smooth, plan passes through 220, 320, and 400 grit.
Choosing an Abrasive Material
Grit number is only half the equation. The abrasive mineral bonded to the paper determines durability and how well the sheet suits different materials. The same grit in different minerals can behave very differently on the same workpiece.
Aluminum oxide
Aluminum oxide is the standard all-purpose abrasive. It fractures as it dulls, exposing fresh cutting edges, which extends its life on wood and painted surfaces. For most home sanding, aluminum oxide is the safe default.
Silicon carbide
Silicon carbide is sharper and harder than aluminum oxide, which makes it the choice for metal, glass, and wet sanding. It cuts fast but wears out sooner on wood, and it is the usual abrasive found on waterproof paper.
Ceramic and garnet
Ceramic grains are the most aggressive and longest-lasting, but they cost more, so they appear on high-end belts and discs for production work. Garnet is a natural mineral that cuts wood well and dulls quickly, a classic choice for hand sanding furniture. The trade-offs among aluminum oxide, silicon carbide, and ceramic abrasives matter most when a project runs through many sheets or demands a specific scratch pattern.
The bond that holds the grains also changes performance. Resin-bonded grains hold longer than glue-bonded grains, and some papers carry a stearate coating that keeps them from loading up when sanding between finish coats. A premium sheet removes more material per pass and lasts longer, which pays off on large surfaces like tabletops and doors.
| Abrasive | Best for | Durability | Typical cost |
|---|---|---|---|
| Aluminum oxide | Wood, paint, general use | Good | Low |
| Silicon carbide | Metal, glass, wet sanding | Fair | Moderate |
| Ceramic | Production sanding, heavy stock removal | Excellent | High |
| Garnet | Hand sanding furniture | Fair | Low |
Matching Grit to Common Projects
Projects fail when the first grit is too coarse or the last grit is too fine. The reliable pattern is to step down through the scale: start coarse enough to remove the defect, then move to finer grits until the surface reaches the finish you want.
Skip no more than one grit band at a time. Jumping from 80 to 220 grit forces the fine paper to remove the deep scratches left by the coarse sheet, which wastes time and wears the sheet out. A sequence of 80, 120, and 150 grit delivers a flat, scratch-free surface faster than any single grit could.
Wood furniture and trim
For bare wood, start with 80 or 100 grit to remove machining marks, move to 120, then finish with 150 before stain. Between finish coats, use 220 or 320 grit to knock down raised grain. Exterior work continues the same staged approach used when choosing the right deck stain and finish for outdoor wood.
Paint and finish prep
To scuff paint before repainting, use 120 to 150 grit, which roughens the surface without cutting through to bare wood. To strip paint entirely, start at 60 or 80 grit and step down the scale. Feather the edges of repaired areas so the new coat blends into the old.
Drywall sanding
Drywall compound needs open-coat paper from 100 to 150 grit, which resists clogging. Finer paper loads up quickly and polishes the compound instead of leveling it. Use 220 grit only for a final skim over feathered edges before priming.
| Project | Starting grit | Finishing grit |
|---|---|---|
| Bare wood furniture | 80 | 150 |
| Repainting walls | 120 | 150 |
| Drywall joint compound | 100 | 150 |
| Between finish coats | 220 | 320 |
| Metal | 120 | 400 |
Tools, Technique, and Buying Tips
Choosing sanding tools
Paper performs only as well as the tool that drives it. Orbital sanders suit flat surfaces, detail sanders reach corners, and sanding blocks keep hand work flat. Drywall has its own equipment needs, and a drywall sanding tools and techniques guide covers the pole sanders and vacuum attachments that keep dust under control.
Technique that saves paper
- Start with the coarsest grit needed and step down gradually.
- Sand with the wood grain on the final pass.
- Let the paper do the work; heavy pressure clogs grit faster.
- Clean or replace the sheet when the cut slows.
- Vacuum between grit changes so loose abrasive does not scratch the fresh surface.
Buying and storing sandpaper
Buy small multi-grit packs for occasional projects and full boxes of the grits you use constantly. Store sheets flat in a dry place, because humidity softens the backing and ruins the adhesive bond. Match the paper size to the sander, or buy full sheets and cut them to fit.
Sanding safely
Sanding produces fine dust that irritates the lungs, so wear a dust mask or hook the sander to a shop vacuum. Sanding painted surfaces in older homes can expose lead paint; test before sanding and switch to wet methods if the test is positive. Keep the work area ventilated and let dust settle before cleaning up with a damp cloth rather than a dry broom.
Selecting grit is a repeatable process: identify the material, choose the abrasive type, and step through coarse-to-fine passes until the surface matches the finish. The same decision framework applies across the job site, from custom door design for home builders to choosing fasteners, finishes, and sanding supplies.