# Calculate Interest

• 10-08-2010, 03:15 AM
hacikho
Calculate Interest
On my BankAccount program one of the method should calculate interest as below.

Calculate interest: The interest is compounded daily and is calculated as follows

IN = P(1 + i)n – P (n is power, I could not make it as power visually in here)
Where

IN is interest

P is Principle

i is the daily percentage rate calculated as yearly interest / 365

n is the number of days(I make it 30 on my program to calculate monthly interest)

User will enter the balance and annual interest rate. Here is my method and result. I could not apply this formula to my method correctly because my result in not correct. If you guys give me a hand that I will appreciate you.
Code:

```//Interest Calculation     public void interest()     {             interest = balance * Math.pow((1 + annualInterestRate/365), 30)- balance;     }```
Code:

```Enter Your Name: john Enter Your Account Number: 35 Enter Your Begining Balance 200 Enter Your Deposit 100 Enter Your Withraw 200 Enter the Annual Interest Rate 10 Account Holder Name: john Account Number 35 [COLOR="Red"]Account Balance: 100.0 Daily Interest Rate 0.0273972602739726 Monthly Interest 124.98424052172155 Account Balance after Interest Added 224.98424052172155[/COLOR] Process completed.```
• 10-08-2010, 03:53 AM
Zack
What is the value & variable type of annualInterestRate? (Note that it should be a double, otherwise its division by 365 may result in undesired rounding.)
• 10-08-2010, 04:31 AM
hacikho
value is 10 and data type is double
• 10-08-2010, 04:47 AM
Zack
If you want it to be a 10% annual interest rate, then its value should be 0.1, not 10.0. When using 10, I get the same number as your program. When using 0.1, I get \$0.825191... which seems right.
• 10-09-2010, 04:15 AM
hacikho
Thanks I was assuming when I put 10 it was 10% however i was wrong, so when I enter 0.1 I have correct value