IEEE double precision (used by Excel and almost all other numerical software) can exactly represent all 15 digit integers, but only some integers with more than 15 digits. Rather than repeatedly explain why 9876543210123457 turns into 9876543210123456, MS chose to display only 15 digits, as documented in Help.
When you enter a number in a cell, Excel truncates it to 15 significant digits before converting to binary, so to accurately enter more than 15 digits, you have to write it as a formula involving constants of no more than 15 digits each, or else poke it from VBA using CDbl("1234123412341234").
To see more than 15 digits of the value that was actually stored from your formula, try the conversion functions posted at http://groups.google.com/group/microsoft.public.excel/msg/b106871cf92f8465
Jerry
"mark_timberlake[ at ]hotmail.com" wrote:
[Quoted Text] > I have a series of 16 and 18 digit numbers that I am trying to store and work > with. > If for example I have the number 1234123412341234 and I leave the field > unformatted I get '1.23412E+15' which is fine. If I change the cell > formatting to 'number' w/o decimals I get '1234123412341230'. What has > happened to my last '4'? Why is it now a cheeky '0'? This seems to happen > with all digits after and including the 16th. > > Any help appreciated. > > Mark
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