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# Financial.IRR Method

.NET Framework 4.5

Returns a Double specifying the internal rate of return for a series of periodic cash flows (payments and receipts).

Namespace:  Microsoft.VisualBasic
Assembly:  Microsoft.VisualBasic (in Microsoft.VisualBasic.dll)
```public static double IRR(
ref double[] ValueArray,
double Guess
)
```

#### Parameters

ValueArray
Type: System.Double[]

Required. Array of Double specifying cash flow values. The array must contain at least one negative value (a payment) and one positive value (a receipt).

Guess
Type: System.Double

Optional. Object specifying value you estimate will be returned by IRR. If omitted, Guess is 0.1 (10 percent).

#### Return Value

Type: System.Double
Returns a Double specifying the internal rate of return for a series of periodic cash flows (payments and receipts).
ExceptionCondition
ArgumentException

Array argument values are invalid or Guess <= -1.

The internal rate of return is the interest rate received for an investment consisting of payments and receipts that occur at regular intervals.

The IRR function uses the order of values within the array to interpret the order of payments and receipts. Be sure to enter your payment and receipt values in the correct sequence. The cash flow for each period does not need to be fixed, as it is for an annuity.

IRR is calculated by iteration. Starting with the value of Guess, IRR cycles through the calculation until the result is accurate to within 0.00001 percent. If IRR cannot find a result after 20 tries, it fails.

In this example, the IRR function returns the internal rate of return for a series of five cash flows contained in the array Values(). The first array element is a negative cash flow representing business start-up costs. The remaining four cash flows represent positive cash flows for the subsequent four years. Guess is the estimated internal rate of return.

```' Define money format.
Dim MoneyFmt As String = "###,##0.00"
' Define percentage format.
Dim PercentFmt As String = "#0.00"

Dim values(4) As Double
values(0) = -70000
' Positive cash flows reflecting income for four successive years.
values(1) = 22000
values(2) = 25000
values(3) = 28000
values(4) = 31000

' Use the IRR function to calculate the rate of return.
' Guess starts at 10 percent.
Dim Guess As Double = 0.1
' Calculate internal rate.
Dim CalcRetRate As Double = IRR(values, Guess) * 100
' Display internal return rate.
MsgBox("The internal rate of return for these cash flows is " &
Format(CalcRetRate, CStr(PercentFmt)) & " percent.")
```

#### .NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

#### .NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.