Just paste create a new module and then paste this source code into it. You can name the module basBaseConversions.
'----------------------------------------------------------------------
'
' Module Name: basBaseConversions
' Written By: Pedro Dias
' C&D Programming Corp.
' Create Date: 1/99
' Copyright: Copyright 1999 by C&D Programming Corp. Source
' code may not be reproduced except for use in a
' compiled executable. All rights reserved. If
' you would like to reprint any or all of this
' code please email us at info@codeoftheweek.com
'----------------------------------------------------------------------
Option Explicit
Function AnyBase(sValueToConvert As String, iBaseIn As Integer, iBaseOut As Integer) As String
Dim i As Integer, iNumOfDigits As Integer
Dim iValue As Integer ' the ASCII value of a digit
Dim DecimalAmount As Long ' corresponding value of sValueToConvert in Decimal
Dim sTemp As String
On Error GoTo ErrorTrap
iNumOfDigits = Len(sValueToConvert)
sValueToConvert = UCase(sValueToConvert)
'
' loop through each character and convert one by one.
'
For i = 1 To iNumOfDigits
iValue = Asc(Mid(sValueToConvert, i, 1))
Select Case iValue
Case 48 To 57: ' values 0 through 9
iValue = iValue - 48
Case 65 To 90: ' values A through Z, adjust to make A=10, B=11, etc
iValue = iValue - 65 + 10
End Select
If iValue >= iBaseIn Then 'This will occur if the sValueToConvert
Error 51 'is not in iBaseIn. Example: the F is greater than 8
End If 'sValueToConvert = "123F6" and iBaseIn = 8
' build the decimal value of sValueToConvert.
DecimalAmount = DecimalAmount + ((iBaseIn) ^ (iNumOfDigits - i) * (iValue))
Next i
' convert the decimal value determined above into the appropriate
' base according to the number passed in iBaseOut
While (DecimalAmount > 0) Or (sTemp = "")
iValue = DecimalAmount Mod iBaseOut
DecimalAmount = DecimalAmount \ iBaseOut
Select Case iValue
Case 0 To 9: iValue = iValue + 48
Case 10 To 35: iValue = iValue + 65 - 10
End Select
sTemp = Chr$(iValue) & sTemp
Wend
' return the string built above.
AnyBase = sTemp
Exit Function
ErrorTrap:
Err.Raise Err.Number, "AnyBase", Err.Description
End Function