CAT is a national level exam conducted by IIMs for the admission in 20 IIMs & other 100+ B School. It is a computer based test consisting multiple choice objective type questions from Data Interpretation and Logical Reasoning, Verbal Ability and Reading Comprehension, Quantitative Ability.

GMAT is considered to be an International management entrance examination conducted by the Graduate Management Admission Council for the admission in around 2,000 B-schools across 82 countries. A student can take the exam 5 times in a year & there should be atleast 16 days gap in between two GMAT Attempts.

To check complete information about CAT & GMAT you can go through with given below links.

CAT

GMAT

Good Luck!