# NPer Function

Visual Studio .NET 2003

Returns a Double specifying the number of periods for an annuity based on periodic, fixed payments and a fixed interest rate.

```Function NPer( _
ByVal Rate As Double, _
ByVal Pmt As Double, _
ByVal PV As Double, _
Optional ByVal FV As Double = 0, _
Optional ByVal Due As DueDate = DueDate.EndOfPeriod _
) As Double
```

#### Parameters

Rate
Required. Double specifying 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.
Pmt
Required. Double specifying payment to be made each period. Payments usually contain principal and interest that doesn't change over the life of the annuity.
PV
Required. Double specifying 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
Optional. Double specifying 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
Optional. Object of type `Microsoft.VisualBasic.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.

#### Exceptions/Errors

Exception type Error number Condition
ArgumentException 5 Rate <= -1.
ArgumentException 5 Rate = 0 and Pmt = 0

#### Remarks

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

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.

#### Example

This example uses the NPer function to return the number of periods during which payments must be made to pay off a loan whose value is contained in `PVal`. Also provided are the interest percentage rate per period (`APR / 12`), the payment (`Payment`), 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 TestNPer()
Dim FVal, TotPmts As Double
Dim PVal, APR, Payment As Double
Dim PayType As DueDate
Dim Response As MsgBoxResult
FVal = 0   ' Usually 0 for a loan.
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.
Payment = CDbl(InputBox("How much do you want to pay each month?"))
Response = MsgBox("Do you make payments at the end of month?", MsgBoxStyle.YesNo)
If Response = MsgBoxResult.No Then
PayType = DueDate.BegOfPeriod
Else
PayType = DueDate.EndOfPeriod
End If
TotPmts = NPer(APR / 12, -Payment, PVal, FVal, PayType)
If Int(TotPmts) <> TotPmts Then TotPmts = Int(TotPmts) + 1
MsgBox("It will take you " & TotPmts & " months to pay off your loan.")
End Sub
```

#### Requirements

Namespace: Microsoft.VisualBasic

Module: Financial

Assembly: Microsoft Visual Basic .NET Runtime (in Microsoft.VisualBasic.dll)