Table comparing sandpaper grit standard in Europe and USA
The below table is originally from Wkipedia, but with some slight changes. What it shows is two colored sections, a section where the difference is small enough to not matter too much (green) and a section from where difference is huge and must be thought of (red). As can be seen, it is only when using finer grits that the difference need to be considered. But in the fine grits, the difference is huge.
http://www.mibnet.se/home-improvemen...standards.html