There are multiple MBA entrance exams. Some of these are as below with their tentative time. However these can change slightly depending on conditions.

CAT- Late November- Early December
SNAP- Mid December
IIFT- Late November- Early December
NMAT- October- December
CMAT- Feb- March
XAT- January first Sunday

There are more than 10 competitive exams held for MBA Admission across colleges in India.
The dates are different for all of fhem as listed below:-

• CAT- 26/11/2017
• XAT - 7/1/2018
• IIFT 3/12/2017
• SNAP 17/12/2017
• CMAT 20/1/2018
• MAHCET 4/3/2018
• NMAT 18/12/2017
• MAT 4/2/2018
• ATMA 14/1/2018
• IBSAT 2/1/2018
• TISSNET 6/1/2018
• MICAT 17/12/2017.

MAJORITY of exmas held duribg November to February 2017-18 hence your advised to start registeribg flr exams like CMAT, CET, MAT for February.