How Home Loan EMI is calculated.

by Manish Chauhan on January 18, 2008

In this post we will learn how do we calculate monthly EMI for home Loan and how increasing Tenure does not help much after a certain point.

In Housing Finance , Equated Monthly Installment(EMI) refers to the monthly payment towards interest and principal made by a borrower to a lender. EMI is calculated using a formula that considers .

- Loan Amount
- Interest Rate
- Loan Period

EMI = ( L x i ) X (( 1+ i ) ^ N) / ([(1+i)^N] – 1)

Where,

L = Loan amount
i = Interest Rate (rate per annum divided by 12)
^ = to the power of
N = loan period in months

Assuming a loan of Rs 1 Lakh at 11 percent per annum , repayable in 15 years, the EMI calculation using the formula will be :

EMI = (100000 x .00916) x ((1+.00916)^180 ) / ([(1+.00916)^180] – 1)

====> 916 X (5.161846 / 4.161846)

EMI = Rs 1,136

Note : i = 11 percent / 12 = .11/12 = .00916

EMI caculator : http://contentlinks.asiancerc.com/mt/tools.asp?pageSubType=emi_calculator

Read : what is Net Present Value ?

Well i would like to raise a point here , or a question ??

Q. How much benefit we get by increasing the Tenure of the Loan. Considering a Loan of Rs 30 Lacs at 12% interest rate.

I did a bit of my so called “mathematical skills” … and found out that EMI is of form

EMI(n) = C1 X C2^n / C2^n-1 , where
C1 = L * i
C2 = 1+i

So the difference in the EMI value for n+1 and n is nothing but

by a bit of caculation i got :

EMI(n) – EMI(n+1) = C1 x (C2^2n – C2^n) / (C2^2n – 1)

and when n becomes very large … and appling limit, we get

Lim C1 x (C2^2n – C2^n) / (C2^2n – 1)
-> Inf

=>

Lim C1 / C2^n
n->Inf

and as C2 > 1 (C2 = 1+i)

=>

Lim C1/C2^n = 0
n->Inf

Or in other words if we differentiate the EMI formula … we get a constant …

It shows and proves that the difference in EMI value is not very significant copmpared to the change in tenure and at one stage its almost of no gain to increase the tenure.

To show this argument : i would like to present an example, considering my old question:

Q. How much benefit we get by increasing the Tenure of the Loan. Considering a Loan of Rs 30 Lacs at 12% interest rate.

I am listing down the EMI value for different Tenures from 10 years to 100 years

Tenure EMI Differnce in EMI when tenure increased by 5 years

10 43041 7036
15 36005 2972
20 33032 1435
25 31596 738
30 30858 391
35 30466. 211
40 30254 115
45 30139 63
50 30076 34
55 30042 18
60 30023 10
65 30012 5
70 30007 3
75 30003 1
80 30002 0.95
85 30001.17 0.52
90 30000.64 0.29
95 30000.35 0.159

What it tells us is that it’s almost useless to extend the tenure after some time …





To get Free updates in Future, Subscribe to this Blog. Enter your email address

Post Footer automatically generated by Add Post Footer Plugin for wordpress.

{ 1 trackback }

How to Calculate Net Present Value (NPV) and how to use it
December 11, 2009 at 2:24 am

{ 7 comments… read them below or add one }

1 stock market September 11, 2009 at 12:36 am

You are brilliant! Thank you for sharing your wonderful ideas and tools.

Reply

2 Manish Chauhan September 11, 2009 at 3:29 pm

@Stock trading

Thanks a lot .. what do you think about the maths done here :) .. just curious :)

Manish

Reply

3 Anonymous September 30, 2009 at 3:20 am

I have taken a fixed home loan of 20,00,000 for 15 years with 9.5% rate. My EMI was 22K, however i started paying 30K instead to save some interest.
Current outstanding is 17.40 Lacs,
With my calculation i will be closing the loan in next 6 years.
I have some money now around 1 Lac, Should i pay this one and save interest or invest in a mutual fund and continue as per plan to close in 6 years.

Reply

4 Ajeet Khurana January 8, 2010 at 6:08 pm

Brilliant conclusion man. Thanks for this :) I saw this blog today for the first time, but I will visit again :)

Reply

5 Manish Chauhan January 8, 2010 at 6:14 pm

Hi Ajeet

Thanks for stopping by and reading . I am sure you will get amazing things in future too :)

Manish

Reply

6 Amarnath January 21, 2010 at 10:08 pm

Manish ,

U Rockz . Tihs blog makes me to re check my math skills ;) . U r simply awsome

Reply

7 manish January 21, 2010 at 10:59 pm

Amarnath

Thanks man … I am sure you are talking about the calculas part :)

Manish

Reply

Leave a Comment

  • Poll

  • Featured Video

  • Connect on Facebook




  • Sponsors

    Alexa Review
  • Jagoinvestor on TwitterJagoinvestor on FacebookJagoinvestor RSS FeedJagoinvestor EmailGet Mobile Updates