[chipsa]

Very much depends on the rating. A residential panel is something like 65”x40”. A commercial sized panel is something like 80”x40”. The cell size is relatively constant, but the bigger panels are 6x12 cells instead of 6x10. Newer panels have more efficient cells, and so higher power.

Panel manufacturers can also do odder sizes as required. Example: q-cell does a 94x51” panel. This is 6x22 cells, but different sized cells as well.

Most panels are 6x, because that results in an open circuit voltage of just shy of 50V, which is convenient for code compliance.