I have taken a 7 years loan of 450 000 for a car in January 2017 with monthly payment of 7077. The interest rate was 8.25% which means that the total repayment is 593878 after 7 years. As from November 2017 till now, since the interest rate has changed, I have been paying 6972.69 par month. Can any one please tell me what is the new interest rate since November 2017 and also how much I left I need to repay. I am at lost about how to calculate that with floating interest.
Similar to the answer to this question:-
s = principal r = monthly interest rate n = number of months d = monthly payment s = 450000 r = 8.25/100/12 n = 7*12
Payment amount to pay off at 8.25% over 7 years (ref. formula)
d = r (1 + 1/((1 + r)^n - 1)) s = 7069.98
However, the interest rate changes after 10 months.
For calculations with rate changes calculate the principal remaining at the time the rate changes, then treat the next period as a fresh amortisation.
Calculating the principal remaining after 10 months,
x, resetting the value of
x = 10 s = (d + (1 + r)^x (r s - d))/r = 408984.76
Continuing with new figures.
n = 7*12 - x d = 6972.69
Numerically solving annuity equation
s = (d - d (1 + r)^-n)/r for
r = 0.00647044
The new interest rate is
12 r = 7.76452 %