Here are my inputs

1) To calculate these fields dynamically while displaying them on the User interface and not save in DB (while making reports, again calculate these fields dynamically and show), or

It is right based on the normalization concept. But it takes more time to retrieve data

2) Add new formula field columns in database table to save each field, which would make the table size bigger, but reporting becomes easier.

It is wrong based on the normalization concept. But it is faster to retrieve data.

3) Add only those columns in database on which reports needs to be made, calculate rest of the fields dynamically on screen.

It is a kind of compromization. You may create a cube, or something like that.