Tag Archives: sandpaper

Sandpaper Grits

We all know about sandpaper grit. The lower the grit, the more coarse the sandpaper is, while the higher the grit, the less material it removes (and the smoother you can make your surface). You may have noticed that sometimes the grit has a “P” preceding the number. What does that mean?

It turns out sandpaper grit is measured in two different scales. As with most types of measurements, you have the US way and the European way. The US scale uses the bare numbers and is known as CAMI (Coated Abrasive Manufacturers Institute). The European scale is the “P” grade, and is known as FEPA (Federation of European Producers of Abrasives).

Both scales are based on the diameter of the average particle size in micrometer (µm), also know as a micron (one millimeter equals one thousand microns). Below is a chart comparing the two.

Average particle size CAMI FEPA
15.3 P1200
16 600
18.3 P1000
20 500
21.8 P800
23  400
25.75 P600
28.8 360
30.2 P500
35 P400
36 320
40.5 P360
44 280
46.2 P320
52.5 P280
53.5 240
58.5 P240
65 P220
66 220
78 180 P180
93 150
97 P150
116 120
127 P120
141 100
156 P100
192 80
197 P80
260 P60
268 60

You can see that the two different grit scales are fairly comparable at the coarser end of things.  In fact, 180 and P180 are exactly the same. But once they start getting finer than about 240, the two scales really start to diverge; 600 and P1200 are nearly identical.

Most sandpaper sold in the US uses CAMI, but you can find some brands with the “P” scale; Klingspor is one that comes to mind. The two scales can get tricky at the finer ends of things. If you read a tutorial that says to sand something at 800 grit, but you grab a sheet of P800 sandpaper, you’ll be using something far more coarse than what was intended.

But now you know.