Sandpaper packaging is covered in numbers, and none of them mean anything until someone explains the system. Once you understand what the grit number tells you, choosing sandpaper stops being a guessing game. Here is how the numbers work and how to move through them on a real project.
What the grit number actually means
The number on a sheet of sandpaper refers to how many abrasive particles fit in a square inch of the paper. A low number, like 40 or 60, means large, widely spaced particles that cut aggressively and leave deep scratches. A high number, like 320 or 400, means small, densely packed particles that remove very little material and leave a fine scratch pattern. The rule to remember: lower number, coarser grit, more aggressive. Higher number, finer grit, more polish.
Grit ranges and what they’re for
- 40 to 60 (extra coarse). Removing paint, leveling badly warped boards, or heavy shaping. Rarely needed on a beginner project unless you are restoring old wood.
- 80 to 100 (coarse). Removing mill marks, flattening glue-ups, and initial shaping. This is usually where a rough board starts.
- 120 to 150 (medium). The workhorse range. Most of your sanding time on a typical project happens here, smoothing out the marks left by coarser paper.
- 180 to 220 (fine). The step right before finishing. This is the grit most beginner projects should stop at before applying a finish.
- 320 and up (very fine). Sanding between coats of finish, or polishing a surface that is already smooth. Not needed for raw wood prep on most builds.
A simple grit progression
The general method is to start with the coarsest grit that removes your surface problem, then work up in steps that roughly double the number each time. A practical progression for a typical beginner project looks like 80, then 120, then 180 or 220. Each grit’s job is to remove the scratches left by the previous one, so skipping too many steps just means the deeper scratches from the coarse grit are still there under a light polish.
You do not need every grit in existence. Three or four well-chosen grits will cover nearly everything in a beginner’s shop. For the sanding technique itself, including how to work with the grain and how to tell when you are done, see our full guide on how to sand wood.
Matching grit to the task
Not every project starts at the same point. A rough-sawn board fresh from the lumber yard needs to start around 80 grit. A board that is already planed smooth might only need 150 to knock down light machine marks before moving to 220. Painted pieces getting a fresh coat often only need a light scuff with 150 or 180 to help the new paint grip, not a full strip-down. Match your starting grit to how rough the surface actually is rather than automatically starting at the coarsest paper you own.
Finish also affects your target grit. Wood taking a film finish like polyurethane usually looks best stopped around 220, since going finer can burnish the wood and make stain absorb unevenly. Wood taking an oil finish can sometimes go a little finer, since oil tends to highlight surface texture more than film finishes do.
Hand sanding vs. power sanding
The grit numbers mean the same thing whether you are using a sanding block by hand or an orbital sander, but power sanders cut faster and can remove more material than intended if you linger in one spot. When using a power sander, keep it moving and let the grit progression do the work rather than pressing hard with one grit to force results. Hand sanding gives you more control for edges, corners, and any area where an orbital sander’s rounded pad cannot reach flat.
Common mistakes to avoid
- Starting too fine. If a board still has visible mill marks or dips, starting at 220 will take a very long time and may never fully remove them.
- Skipping too many grits. Jumping from 80 straight to 320 leaves 80 grit scratches under a finer surface polish that only shows once finish is applied.
- Sanding across the grain. Regardless of grit, sanding against the wood grain leaves scratches that catch the light and show through most finishes.
- Reusing worn-out paper. Sandpaper dulls with use. A worn sheet stops cutting and just burnishes the surface, which wastes time and can burn some woods.
Once your sandpaper collection and progression make sense, the rest of finishing gets much easier. For the next step after sanding, our guide to wood finishing for beginners walks through choosing between oil, poly, and wax. And if you are just getting your shop set up for a first project, start with the beginner weekend guide or browse our list of beginner projects to put these grits to use. If you would rather follow ready-made cut lists and plans while you practice, our TedsWoodworking review covers what is inside that plan library.