This ranges from120 to 220 grit and is one of the most commonly used grades in home DIY projects. Painting projects often use 120-180 grit for sanding down previously painted surfaces. It gets rid of any minor imperfections and roughs up the surface to provide good adhesion for a new coat of paint. It is also used on bare wood to smooth out ready for the first coat of paint or varnish.

The Grit grades below are a guide to the commonly found sandpapers available and thier uses. Manufacturers differ on the scale but this is the average. This sits below coarse sandpaper and includes 24 and 36 grit sandpaper. It is used for jobs that have a lot of paint or varnish to remove. It's often used on rough timber that needs to be smoothed out and the first sanding when sanding floorboards. What does the P mean in sandpaper grits?

Grits above 320 such as 400 to 600 are typically used to get a really fine finish on wood ready for waxing or polishing. It can also be used to smooth out a top coat and fine wet sanding.

Large particles fit through larger holes. Because they’re larger, a standard filtering screen requires fewer of them. Consequently, coarser grits are known by smaller numbers than finer grits, much like larger-diameter wires have smaller gauge numbers in the American Wire Gauge system. Extra-fine (320- and 360-grit): The first of the micro-abrasives, this is primarily for sanding finishes before polishing. It is also the common choice when sanding painted walls, smoothing out plaster and rubbing down filler to blend in with the surface it's on. Super-fine (400-, 500- and 600-grit): Use this for polishing finishes on wood and metal, and to polish bare metal. It comes on waterproof sheets to allow for wet-sanding. Fine (100- and 120-grit): The best utility sandpaper. Fine grades smooth scratches left by coarser grades and rough up painted surfaces before accepting new paint. They’re also good for sanding drywall. When you just need some for hand-sanding, or to use with an orbital sander, this is the grade you’ll most likely use.

Very-fine (150-, 180- and 220-grit): This produces ultra-smooth surfaces on wood. People often use it to scuff-sand lacquer, polyurethane and other finishes before applying another coat. Extra-coarse (24-, 30- and 36-grit): Generally used for preliminary hardwood floor sanding, this usually comes in belts that fit on a drum sander, or disks that fit an edger. Grit measures sandpaper’s coarseness, determined by the size of the abrasive particles on its surface.