This sandpaper grit guide makes grit numbers simple: the lower the number the coarser the paper, and the higher the number the finer the finish. As a rule, start coarse to remove material and old coatings, then work up through the grits to smooth and finish. Match the grit to the job and you will get flawless results with far less effort.
Below we break down each grit range, explain which suits which task, and share the working order that professional painters and cabinetmakers rely on.
What do sandpaper grit numbers mean?
The grit number tells you how many abrasive particles sit per square inch of the paper. Fewer, bigger particles (a low number) cut fast and aggressively; more, smaller particles (a high number) leave a smoother surface.
Coarse grits remove timber, rust and old paint quickly but leave visible scratches. Fine grits remove almost nothing but polish the surface silky-smooth. The whole skill of sanding is climbing through the grits in order so each pass erases the scratches left by the one before.
Coarse grit (40 to 60): heavy stripping and shaping
Coarse paper is your demolition crew. Reach for 40 to 60 grit when you need to strip old paint or varnish, sand back rough-sawn timber, or level an uneven surface fast.
It cuts aggressively, so keep it moving and never use it for finishing, because the deep scratches are hard to remove later. This is also the grit to grab before treating rusty metal with a product like Dulux Autoshield rust converter spray, since a keyed, flaking-free surface helps the treatment bond.
Medium grit (80 to 120): general prep and smoothing
Medium grit is the workhorse of most projects. Use 80 to 120 grit to smooth timber after coarse sanding, round over sharp edges, remove light scratches and prepare bare surfaces for paint or stain.
For most DIY jobs, 120 grit is the sweet spot before you apply a primer or undercoat. It leaves just enough tooth for the paint to grip while still feeling smooth to the hand. You will find sanding sheets, discs and blocks in a good selection of tool accessories to suit whatever sander or hand block you own.
Fine grit (150 to 240): finishing and pre-paint prep
Fine grit refines the surface ready for a beautiful finish. Use 150 to 180 grit as a final pass on bare timber before staining, and 220 to 240 grit to lightly key a surface before the first coat of paint.
This range is also perfect for a quick scuff-sand between coats, knocking back any raised grain or dust nibs so the next layer lays down glass-smooth. A light key with 240 grit before spraying a fast-drying finish such as Dulux flat black spray paint helps it adhere and levels beautifully.
Extra fine grit (320 and up): between-coats and polishing
Very fine grits of 320, 400 and beyond are for perfectionists. Use them wet or dry to sand between coats of paint, lacquer or clear finish, and to buff out imperfections for a mirror-smooth result.
These grits barely remove material, so they will not damage your finish, but they make each successive coat feel silkier. They shine when you are sealing a stain or ceiling with a product like Zinsser Covers Up ceiling paint aerosol and want a spotless, professional look.
Which grit suits which person or job?
Not sure where to start? Here is a quick match-up of common jobs to the right grit range, so you buy exactly what you need.
| Job | Grit range | Why |
|---|---|---|
| Stripping old paint or varnish | 40 to 60 | Cuts through thick coatings fast |
| Smoothing rough or sawn timber | 80 to 120 | Levels the surface without deep scratches |
| Final prep before paint or primer | 120 to 180 | Leaves the right tooth for adhesion |
| Final pass before staining timber | 150 to 180 | Smooth enough for even stain uptake |
| Keying a surface before topcoat | 220 to 240 | Light scuff for paint to grip |
| Sanding between coats | 320 to 400 | Removes nibs without cutting through |
How to work through the grits
The golden rule is never skip more than one grade at a time. Jumping from 60 straight to 240 leaves scratches the fine paper cannot erase, so climb in steps such as 60, 120, 180, 240.
- Always sand along the timber grain, not across it
- Let the paper do the work rather than pressing hard
- Wipe or vacuum off dust between grits so grit does not contaminate the next pass
- Replace paper once it stops cutting; clogged paper just burnishes the surface
Keep the workpiece steady while you sand. A simple timber wedge door stop tucked under a hinged panel or a workbench-mounted stop can hold small jobs firm without marking them.
Care, storage and getting the most from your paper
Sandpaper lasts longer when you look after it. Store sheets flat in a dry spot, because humidity softens the backing and loosens the grit, and keep your grits clearly separated so you never grab the wrong number mid-job.
For a longer-lasting kit, stock a spread of grits ahead of time and browse the wider painting consumables range so you have primers, fillers and abrasives on hand before you start. Buying the full set up front saves frustrating trips halfway through a project.
Frequently asked questions
What grit sandpaper should I use before painting?
For most surfaces, finish with 120 to 180 grit before priming bare timber, and lightly key previously painted or glossy surfaces with 220 to 240 grit. This leaves just enough tooth for the paint to grip while keeping the surface smooth. Always wipe off dust before you apply any primer or paint.
Is a higher or lower grit number coarser?
A lower number is coarser. The grit number counts abrasive particles per square inch, so 40 grit has fewer, larger particles that cut aggressively, while 320 grit has many tiny particles that polish gently. Start with a low number to remove material, then climb to higher numbers to smooth and finish.
Can I skip grits to save time?
It is best not to skip more than one grade at a time. Jumping too far, say from 60 straight to 240, leaves coarse scratches the fine paper cannot remove, so you end up sanding longer overall. Progress in steps such as 60, 120, 180, 240 for the fastest, cleanest result.
What is the difference between wet and dry sanding?
Dry sanding removes material faster and suits bare timber and paint stripping. Wet sanding, using water or a lubricant with fine grits of 320 and above, reduces dust, prevents clogging and produces an ultra-smooth finish. Wet sanding is mainly used between coats of paint or clear finish for a flawless surface.
