Excellent, thank you! I'm almost there. I calculated the original area, then ran the intersect tool, then calculated the new area. Then I created a new field and used the field calculator to computer (OriginalArea/NewArea) * 100 to get the percentage. The polygons that are completely inside are labeled as 100%, but the polygons that are 50%, 10%, etc. inside the polygon have weird numbers (for example, one of the slivers that is inside the polygon is calculated as 1328227643.9 (the new area was calculated as 0.00003). I know it's just a matter of my calculations, but how do I fix that? Thanks!!