The usual pattern: If you are a general category candidate and if your UPSC rank is around 90 then you have a fair chance of making it to the IAS. Similarly, a 465 rank for OBC, 650 for SC and 770 for ST should be good enough for IAS. For IFS, a 115 rank for general category, 570 for OBC, 765 for SC and 925 for ST.