PPmt Function Example

This example uses the PPmt function to calculate how much of a payment for a specific period is principal when all the payments are of equal value. Given are the interest percentage rate per period (APR / 12), the payment period for which the principal portion is desired (Period), the total number of payments (TotPmts), the present value or principal of the loan (PVal), the future value of the loan (FVal), and a number that indicates whether the payment is due at the beginning or end of the payment period (PayType).

Dim NL, TB, Fmt, FVal, PVal, APR, TotPmts, PayType, Payment, Msg, MakeChart, Period, P, I
Const ENDPERIOD = 0, BEGINPERIOD = 1    ' When payments are made.
NL = Chr(13) & Chr(10)    ' Define newline.
TB = Chr(9)    ' Define tab.
Fmt = "###,###,##0.00"    ' Define money format.
FVal = 0    ' Usually 0 for a loan.
PVal = InputBox("How much do you want to borrow?")
APR = InputBox("What is the annual percentage rate of your loan?")
If APR > 1 Then APR = APR / 100    ' Ensure proper form.
TotPmts = InputBox("How many monthly payments do you have to make?")
PayType = MsgBox("Do you make payments at the end of month?", vbYesNo)
If PayType = vbNo Then PayType = BEGINPERIOD Else PayType = ENDPERIOD
Payment = Abs(-Pmt(APR / 12, TotPmts, PVal, FVal, PayType))
Msg = "Your monthly payment is " & Format(Payment, Fmt) & ". "
Msg = Msg & "Would you like a breakdown of your principal and "
Msg = Msg & "interest per period?"
MakeChart = MsgBox(Msg, vbYesNo)    ' See if chart is desired.
If MakeChart <> vbNo Then
    If TotPmts > 12 Then MsgBox "Only first year will be shown."
    Msg = "Month  Payment  Principal  Interest" & NL
    For Period = 1 To TotPmts
        If Period > 12 Then Exit For    ' Show only first 12.
        P = PPmt(APR / 12, Period, TotPmts, -PVal, FVal, PayType)
        P = (Int((P + .005) * 100) / 100)    ' Round principal.
        I = Payment - P
        I = (Int((I + .005) * 100) / 100)    ' Round interest.
        Msg = Msg & Period & TB & Format(Payment, Fmt)
        Msg = Msg & TB & Format(P, Fmt) & TB & Format(I, Fmt) & NL
    Next Period
    MsgBox Msg    ' Display amortization table.
End If