I have form 16, now I wanted to calculate tax for bank intrest income. How can I caluculate this?

I got form 16 from my current employer however Income accrue from bank interest is not mentioned. I wanted to pay self assesment tax for bank interest. How can I arrive at the Total Tax liability given the fact that I already have TDS certificate so I would not like to caluculate over all tax using tools where u have to mention salary details and interest