java - Monthly payment calculator returning wrong payment

I am supposed to make a monthly payment calculator in java with the given formula.
The formula for me to use is

M = P * i/ 1 - (1+i)^-n

where

• P is the loan principal (i.e. the amount borrowed)


• i is monthly interest rate (annual_interest_rate / 12; expressed as decimal)


• N is time (number of monthly payments in total years of loan; i.e. years * 12)

The code below is my attempted function to get the monthly payment.

But if I put in 6 years with a loan amount of 200, I get 140 using the formula.
I am stumped as to why I get that number. Any help would be appreciated

public static int calMonthlyPay(double loanAmt, int y)  {
    double m = 0.0, interest = 0.0, annualIRate = 0.0;
    double months = 0.0;

    months = y * 12; 
    annualIRate = getAnnualIRate(y);
    interest = annualIRate / 12;

    System.out.println(interest);
    System.out.println(months);
    System.out.println(loanAmt);
    System.out.println(y);

    m = (loanAmt * (interest - Math.pow((1 + interest), -months))); // This is my formula calculation

    System.out.println(m);

    return 0;
}

private static double getAnnualIRate(int y)  {
    switch (y) {
    case 2:
        return 5.7;
    case 3:

        return 6.2;
    case 4:
        return 6.8;
    case 5:
        return 7.5;
    case 6:
        return 8.4;
    default:
        return 8.4;
    }

}