Hi Shamit,
Round 2 deadlines for most US-based top ranked MBA programs are between early-mid Jan 2017. The GMAC website (
www.mba.com) provides registration requirements and the available slots at testing sites near you. I suggest taking the GMAT as early as you can since we're rapidly approaching Sept and there are other parts of the applications that are equally important and would require some time commitment to prepare if you want to submit application packages that stand out.
Keep in mind that if you're targeting certain schools, you want to try to get as close as you can to the average GMAT score or higher. Taking the exam early on gives you time to take it a second time if you want to improve your score before applying in round 2.
Best of luck!
