# XL2000: How to Create Unique Random Integers Between Two Numbers

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##### SUMMARY
In Microsoft Excel, you can create a Microsoft Visual Basic Sub procedure (macro) to create a list of unique (non-repeating) random integers between two other numbers.

This articles describes a sample macro that prompts the user for a starting integer and an ending integer, prompts the user to input the number of random numbers to generate, and then generates a list of unique integers on the active worksheet.
Microsoft provides programming examples for illustration only, without warranty either expressed or implied, including, but not limited to, the implied warranties of merchantability and/or fitness for a particular purpose. This article assumes that you are familiar with the programming language being demonstrated and the tools used to create and debug procedures. Microsoft support professionals can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific needs.
If you have limited programming experience, you may want to contact a Microsoft Certified Partner or Microsoft Advisory Services. For more information, visit these Microsoft Web sites:

Microsoft Certified Partners - https://partner.microsoft.com/global/30000104

For more information about the support options that are available and about how to contact Microsoft, visit the following Microsoft Web site:http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMSTo create and run the macro described in the "Summary" section, follow these steps:
1. Start Excel, and then Press ALT+F11 to start the Visual Basic editor.
2. On the Insert menu, click Module.
3. Type the following code in a module sheet:
``Option ExplicitSub Unique_Numbers()   Dim x As Long, y As Long, z As Long, tempnum As Long   Dim flag As Boolean   Dim i As Integer   Dim foundCell As Range   Application.ScreenUpdating = False   x = Application.InputBox("Enter starting Random Number" _      , "Random Number Generation", 1, , , , , 1)   y = Application.InputBox("Enter ending Random Number" _      , "Random Number Generation", 1000, , , , , 1)   z = Application.InputBox("How many random numbers would" _      & "you like to generate (<15000)?" _          , "Random Number Generation", 100, , , , , 1)   If z = 0 Then Exit Sub   If z > 15000 Then z = 15000   If z > y - x + 1 Then       MsgBox "You specified more numbers to return than " _         & "are possible in the range!"       Exit Sub   End If   Randomize   Cells(1, 1) =  Int((y - x + 1) * Rnd + x)   For i = 2 To z       Do           flag = False           Randomize           tempnum = Int((y - x + 1) * Rnd + x)           Set foundCell = Range("a1", _                  Range("a1").End(xlDown).Address).Find(tempnum)           If Not (foundCell Is Nothing) Then               flag = True           End If       Loop Until Not flag       Cells(i, 1) =  tempnum   NextEnd Sub         						``