# Calculating Monthly Rate of Interest for Home Loan given EMI, Interest and Principal Amount

I have taken a loan with below details:

Loan Start Date: 6th July 2012

EMI Date: 5th Day of Every Month (Initially 21000 and later 22000 per month)

Tenure: 20 Years (This decreases based on the extra amount I pay over and above the EMI)

Interest Charged Date: Last Calendar Day of Every Month

The amount of Interest Charged every month goes up or down based on:
a) Change in Rate of Interest and
b) Remaining Principal Amount

Sometimes I also pay some extra amount over and above the monthly EMI.

The excel sheet below contains all the data I have from my bank statement.

You just need to subtrauct from the payment the diference in the principal and than the rest is interest - $P_i$. The rate is calculated as: ${12}\times{P_i/Principal_at_begining of_month/100}$.