Interest calculation

[saziz]

HI,
I just want to know if I am doing this correct.

I have calculated 7.5% interest on $10,000.00 to be paid in 4 years.
10K times .0075 divided by 12 for months. Which would be 62.50. then
I am adding $200.00 which is going for actual balance payment.
So next month it would be 9,800 times 7.5% divided by 12 months.
Is this correct?
Appreciate your help.
Thank you

Saziz

 

[Guest]

Hi saziz. If you make constant monthly payments on the $10,000, at 7.5%
interest, the monthly payment will be $241.79. If you don't make constant
payments, your method will work, except $200 times 48 months is only $9,600.
You'll have to make 50 payments and will miss the 4-year deadline by 2
months. See the PMT function in Excel. HTH

 

[Guest]

Why not use the imbedded Excel functions to calculate the Payment amount, the
Priciple and Interest?

Using the follow formulas for your example:
Monthly Loan Payment - =PMT(7.5%/12,4*12,10000,0)
Monthly Priciple Payment - =PPMT(7.5%/12,1,4*12,10000,0)
Monthly Interest Payment - =IPMT(7.5%/12,1,4*12,10000,0)

 

[David Benson]

saziz,

Depends on what you are trying to do.

If you are trying to calculate equal monthly payments (i.e., the same amount
paid each month), then you are not correct. Use the PMT built-in function
to calculate that. Remember that this function expects you to tell it the
interest rate per period, so if you're calculating a monthly payment enter
(7.5% / 12) for the interest rate and (4 x 12) for the total number of
periods. For your example, this turns out to be $241.79. The total
interest you will pay is (241.79 x 48 - 10000), or $1,605.87.

If you are just trying to calculate how much interest you pay in any given
month, then yes, you can multiply the outstanding balance by (7.5% / 12)
(which, by the way, is 0.075 / 12). So the amount of interest you would pay
in the first month is indeed 62.50. However, you only pay have to pay
$179.29 on the principal in the first month.

Good luck!

-- David

 

[saziz]

Thank you all for helping.
What I am doing is trying to calculate monthly payments (interest on
balance + $200 towards balance) each month. This is a personal loan.
So this is not going to be equal payment each month. It will decrease
as the balance goes down.

Thanks
Saziz