Average base salary is not calculated as colleges only look for CTC 😅.
But giving an estimate, microsoft has base salary of 13 lpa, which is one of the top IT company.
So average base can be 13–14 lpa which is close to 1 lakh per month without taxes deduction. This is same for old iits as well.
Codenation which has 50 lpa CTC, the inhand salary is close to 90k per month after taxes deduction. Hope you got it 👍