1. ## Calculating Intrest

I'm trying to come up with a formula to calculate intest for me here at work.
Here'e my example i'm working on now.
I have a customer that owes $118.00. Each month late there is a$15.00 late fee
and then 2% intrest added on top of that.
This customer is 11 months late.

What i am having trouble with is getting a formula to addthe 2% intrest each month after the $15.00 charge is added each month. My fomula adds the inital charge, then the late fees, then the intrest based off that. Right now my formula reads 118[initial charge]+15*11[$15 charge for 11 months]((1+.02)^11)-1)

2. Originally Posted by deezeejoey
I'm trying to come up with a formula to calculate intest for me here at work.
Here'e my example i'm working on now.
I have a customer that owes $118.00. Each month late there is a$15.00 late fee
and then 2% intrest added on top of that.
This customer is 11 months late.

What i am having trouble with is getting a formula to addthe 2% intrest each month after the $15.00 charge is added each month. My fomula adds the inital charge, then the late fees, then the intrest based off that. Right now my formula reads 118[initial charge]+15*11[$15 charge for 11 months]((1+.02)^11)-1)

Not sure I'd subtract the 1 at the end. You want the accumulated value of the [initial balance plus late fees]*1.02^late months

That's assuming that when a late charge is tacked on at the end of the month, the 2% is tacked on immediately after before the next month starts and the cycle restarts again.

3. he's something my friend came up with...

Sorry, but all I have is a program oriented answer.

;variables
n=11
i=.02
p=115
f=15

;loop equation
for n
p=(p+f)*(1+i)

;outputs
month 1 118
month 2 135.66
month 3 153.67
month 4 172.05
month 5 190.79
month 6 209.90
month 7 229.40
month 8 249.29
month 9 269.58
month 10 290.27
month 11 311.37
Kind of helps explain, but doesn't help me with all the other 100 customers.

EDIT

Originally Posted by mathceleb

That's assuming that when a late charge is tacked on at the end of the month, the 2% is tacked on immediately after before the next month starts and the cycle restarts again.
That exactly what i need. but thats not what the formula seems to do....
your formula comes out to $351.87 It should come out to$332.90