Trending @Infosys; What should be my Salary ask ?

Passed out Engineering in 2019 from Civil background. Worked for a Civil firm for 1 year then lost job for one and a half year, Got into infy as a Fresher cleared ACON currently having 7.5LPA package working as a DATA MODELLER and now switching the company.

I have documents to show that I have overall 5.5 years of experience (1 year of CIVIL firm and rest IT experience) and relevant experience as Data modeller of 3+ years.

I have cleared Interview rounds for TCS & IBM, interview scheduled for Capgemini and LTI.

What should be my salary ask depending on cumulative experience ?? (I have currently told them range of 15-18) but people are suggesting me to go for 20 also. And Which company would be better if let’s say all are offering around same package ?