Dear Dinesh

Normally course duration of BCA is 3 years, But if you are pursuing it through lateral entry, then the course duration would be 2 years.
If you want to pursue pursue BCA through lateral entry is as follows:
Pass with 50% aggregate marks in Diploma [(any stream) 3 years after 10th ] OR [2years/ 1 year after 10+2] or equivalent.
Please note that eligibility may very institute to institute.

Hope you got my answer.

Goodluck !