# Financial.IRR(Double[], Double) Method

## Definition

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

``public static double IRR (ref double[] ValueArray, double Guess = 0.1);``
``static member IRR : Double[] * double -> double``
``Public Function IRR (ByRef ValueArray As Double(), Optional Guess As Double = 0.1) As Double``

#### Parameters

ValueArray
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
Double

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

#### Returns

The internal rate of return for a series of periodic cash flows (payments and receipts).

#### Exceptions

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

## Examples

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.")
``````

## Remarks

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.