# Financial.Rate(Double, Double, Double, Double, DueDate, Double) Method

## Definition

Returns a value specifying the interest rate per period for an annuity.

`public static double Rate (double NPer, double Pmt, double PV, double FV = 0, Microsoft.VisualBasic.DueDate Due = Microsoft.VisualBasic.DueDate.EndOfPeriod, double Guess = 0.1);`

`static member Rate : double * double * double * double * Microsoft.VisualBasic.DueDate * double -> double`

`Public Function Rate (NPer As Double, Pmt As Double, PV As Double, Optional FV As Double = 0, Optional Due As DueDate = Microsoft.VisualBasic.DueDate.EndOfPeriod, Optional Guess As Double = 0.1) As Double`

#### Parameters

- 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 * 12 (or 48) payment periods.

- Pmt
- Double

Required. The payment to be made each period. Payments usually contain principal and interest that doesn't change over the life of the annuity.

- 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 make the final payment. For example, the future value of a loan is $0 because that is 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.

- Guess
- Double

Optional. The value you estimate is returned by `Rate`

. If omitted, `Guess`

is 0.1 (10 percent).

#### Returns

The interest rate per period for an annuity.

#### Exceptions

`NPer`

<= 0.

## Examples

This example uses the `Rate`

function to calculate the interest rate of a loan given the total number of payments (`TotPmts`

), the amount of the loan payment (`Payment`

), the present value or principal of the loan (`PVal`

), the future value of the loan (`FVal`

), a number that indicates whether the payment is due at the beginning or end of the payment period (`PayType`

), and an approximation of the expected interest rate (`Guess`

).

```
Sub TestRate()
Dim PVal, Payment, TotPmts, APR As Double
Dim PayType As DueDate
' Define percentage format.
Dim Fmt As String = "##0.00"
Dim Response As MsgBoxResult
' Usually 0 for a loan.
Dim FVal As Double = 0
' Guess of 10 percent.
Dim Guess As Double = 0.1
PVal = CDbl(InputBox("How much did you borrow?"))
Payment = CDbl(InputBox("What's your monthly payment?"))
TotPmts = CDbl(InputBox("How many monthly payments do you have to make?"))
Response = MsgBox("Do you make payments at the end of the month?", MsgBoxStyle.YesNo)
If Response = MsgBoxResult.No Then
PayType = DueDate.BegOfPeriod
Else
PayType = DueDate.EndOfPeriod
End If
APR = (Rate(TotPmts, -Payment, PVal, FVal, PayType, Guess) * 12) * 100
MsgBox("Your interest rate is " & Format(CInt(APR), Fmt) & " percent.")
End Sub
```

## 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.

`Rate`

is calculated by iteration. Starting with the value of `Guess`

, `Rate`

cycles through the calculation until the result is accurate to within 0.00001 percent. If `Rate`

cannot find a result after 20 tries, it fails. If your guess is 10 percent and `Rate`

fails, try a different value for `Guess`

.