On Fri, 8 Mar 2013 17:22:07 -0800 (PST), Luciano wrote:

Hi,
Does somebody have any idea about how to develop some VBA function or macro aiming conversion of several numerals types and that could be used for small and large numbers(e.g. 100000000000 in decimal)? The major numerals base for which I need this conversions a
Binary (Base 2)
Ternary (Base 3)
Quaternary (Base 4)
Quinary (Baase 5)
Senary (Base 6)
Septenary (Base 7)
Octal (Base 8)
Nonary (Base 9)
Decimal (Base 10)
Undecimal (Base 11)
Duodecimal (Base 12)
Base 13
Hexadecimal (Base 16)
Vigesimal (Base 20)
and others...

Thanks in advance,
Luciano

Unless you want to reinvent the wheel, it's already been done and available as a free Excel add-in. See http://www.thetropicalevents.com/Xnumbers60.htm which does base conversions and also handles more precision than does Excel.