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Financial.IPmt(Double, Double, Double, Double, Double, DueDate) Method

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Definition

Namespace:
Microsoft.VisualBasic
Assembly:
Microsoft.VisualBasic.Core.dll
Assembly:
Microsoft.VisualBasic.dll
Source:
Financial.vb
Source:
Financial.vb
Source:
Financial.vb

Returns a value specifying the interest payment for a given period of an annuity based on periodic, fixed payments and a fixed interest rate.

public static double IPmt (double Rate, double Per, double NPer, double PV, double FV = 0, Microsoft.VisualBasic.DueDate Due = Microsoft.VisualBasic.DueDate.EndOfPeriod);
static member IPmt : double * double * double * double * double * Microsoft.VisualBasic.DueDate -> double
Public Function IPmt (Rate As Double, Per As Double, NPer As Double, PV As Double, Optional FV As Double = 0, Optional Due As DueDate = Microsoft.VisualBasic.DueDate.EndOfPeriod) As Double

Parameters

Rate
Double

Required. The interest rate per period. For example, if you get a car loan at an annual percentage rate (APR) of 10 percent and make monthly payments, the rate per period is 0.1/12, or 0.0083.

Per
Double

Required. The payment period in the range 1 through NPer.

NPer
Double

Required. The total number of payment periods in the annuity. For example, if you make monthly payments on a four-year car loan, your loan has a total of 4 x 12 (or 48) payment periods.

PV
Double

Required. The present value, or value today, of a series of future payments or receipts. For example, when you borrow money to buy a car, the loan amount is the present value to the lender of the monthly car payments you will make.

FV
Double

Optional. The future value or cash balance you want after you've made the final payment. For example, the future value of a loan is \$0 because that's its value after the final payment. However, if you want to save \$50,000 over 18 years for your child's education, then \$50,000 is the future value. If omitted, 0 is assumed.

Due
DueDate

Optional. Object of type DueDate that specifies when payments are due. This argument must be either DueDate.EndOfPeriod if payments are due at the end of the payment period, or DueDate.BegOfPeriod if payments are due at the beginning of the period. If omitted, DueDate.EndOfPeriod is assumed.

Returns

Double

The interest payment for a given period of an annuity based on periodic, fixed payments and a fixed interest rate.

Exceptions

ArgumentException

Per <= 0 or Per > NPer

Examples

This example uses the IPmt function to calculate how much of a payment is interest when all the payments are of equal value. Given are the interest percentage rate per period (APR / 12), the payment period for which the interest 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).

Sub TestIPMT()
    Dim APR, PVal, Period, IntPmt, TotInt, TotPmts As Double
    Dim PayType As DueDate
    Dim Response As MsgBoxResult

    ' Usually 0 for a loan.
    Dim Fval As Double = 0
    ' Define money format.
    Dim Fmt As String = "###,###,##0.00"
    PVal = CDbl(InputBox("How much do you want to borrow?"))
    APR = CDbl(InputBox("What is the annual percentage rate of your loan?"))
    If APR > 1 Then APR = APR / 100 ' Ensure proper form.
    TotPmts = CInt(InputBox("How many monthly payments?"))
    Response = MsgBox("Do you make payments at end of the month?", MsgBoxStyle.YesNo)
    If Response = MsgBoxResult.No Then
        PayType = DueDate.BegOfPeriod
    Else
        PayType = DueDate.EndOfPeriod
    End If
    For Period = 1 To TotPmts   ' Total all interest.
        IntPmt = IPmt(APR / 12, Period, TotPmts, -PVal, Fval, PayType)
        TotInt = TotInt + IntPmt
    Next Period

    ' Display results.
    MsgBox("You will pay a total of " & Format(TotInt, Fmt) & 
        " in interest for this loan.")
End Sub

Remarks

An annuity is a series of fixed cash payments made over time. An annuity can be a loan (such as a home mortgage) or an investment (such as a monthly savings plan).

The Rate and NPer arguments must be calculated using payment periods expressed in the same units. For example, if Rate is calculated using months, NPer must also be calculated using months.

For all arguments, cash paid out (such as deposits to savings) is represented by negative numbers; cash received (such as dividend checks) is represented by positive numbers.

Applies to

See also