P240 or 240 grit? Converting grit scales

In Europe, the grit number carries a P: it follows the FEPA standard, which defines the average particle size for each grade. American abrasives and many video tutorials give just the number, often with “grit” – that is the CAMI standard (ANSI). Both run from coarse to fine, but not in step.

From P40 to around P220, the particle sizes of both standards are so close that you can treat the numbers as equal: P80 equals 80 grit, P120 equals 120 grit. For wood, filler and metal the difference hardly matters.

In the fine range, the same particle carries a higher number under FEPA than under CAMI. Rough equivalents: P400 is about 320 grit, P600 about 400 grit, P800 about 500 grit, P1200 about 600 grit, P1500 about 800 grit and P2000 about 1000 grit. P1000 sits between 500 and 600 grit.

So if you follow an American guide that says “wet sand with 600”, reach for P1200 – not P600. Use P600 instead and you are sanding two grades coarser than intended, and you will see the scratches later in the clear coat.

Never mix standards within one grit sequence: the rule of “never more than double the number” applies to the numbers of a single standard. All KORNDEX abrasives carry the FEPA P-grade; the grit guide explains every grade and what it is meant for.