Having completed 12th class in Science stream, I don't think its a good option for you to pursue B.Com course.

The subject knowledge that you have gained in the 12th class will nowhere be useful if you pursue B.Com course.

But if you have interest to pursue B.Com course, you can pursue the same.

In several of the colleges direct admission will be offered for B.Com course.

The aspirants should have scored a minimum of 50% of marks in your 12th class to get admission for this course.

However, in some colleges, the admission for the course will be given on merit basis.

Here I am providing you with the examples for two colleges for BCom Hons course:

Goenka College of Commerce and Business Administration, Kolkata
Minimum marks in +2 exam for eligibile BCom (H) course:
(a) for General Category: Minimum 65% in aggregate and Minimum 60% in any of the subjects mentioned below :-
Subjects: Accountancy, Business Economics including Mathematics, Business Organization, Mathematics, Economics, Statistics, Business Mathematics, Secretarial practice and Office Procedure, Financial Accountancy, Elements of Cost Accountancy and Auditing, Book Keeping, Commerce, Cost Accounting and Principles of Management

(b) for SC/ST Category: Minimum 50% in aggregate and Minimum 45% in any of the subjects mentioned above.

(c) for Physically Handicapped Category: Minimum 65% in aggregate and Minimum 60% in any of the above mentioned subjects

St Xavier College, Kolkata

It holds full time B.COM Honours. Bare minimum 60% marks is required at +2 level for taking admission in it. Aspirants must have studied English & Maths/B.Maths/B.Eco with Maths (BEBM) at +2.