>>9052345High Grades are always 1/144th scale.
Real Grade is also 1/144 but are more stylized with overlapping panels and details that never showed up in the shows. (attached pic is a RG Zeong)
PG is Perfect Grade, those are 1/60th scale, (about a foot tall for an average mobile suit) and feature the most internal detail. Really fun big builds, but expensive.
The site I'm getting these pics from is a great site for looking at kits to see what they look like with no paint, with and without panel lines, what the instructions show, etc.
