Yes, I see what you mean about being one off. This should fix that
problem...

=MID("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%",
MOD(SUMPRODUCT(SEARCH(MID(A1,ROW($1:$99),1),
"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%") )-98,43),1)

As for you 16-digit problem... that is Excel's fault... it can only handle
numbers with 15 significant digits. If you are not using this number for
calculating with, then you can either enter the numbers with a leading
apostrophe (which make the entry a text entry). The other possible way to
solve the problem is to format the column as Text so that Excel won't think
you are entering a number. Either way, you won't need to use a leading 1.
Let us know how that works out for you.

--
Rick (MVP - Excel)


"CLI-Art" wrote in message
...
I have to take back the working part. The digit seems to be off by 1 even
taking the
missing leading 1 into consideration. for 900001 ( leaving out all of the
leading #s) I get a check digit of 9 and it should be 10 which would be an
A.



"CLI-Art" wrote:

This one seems to be working. Thank you very much for your help. I am
having an additional issue which is somewhat unrelated, but causing a
miscalculation of the check digit. The number that I am adding a mod 43
check digit to is a 16 digit number and in order to get it to serialize
in
Excel I had to force the initial 1 in with cell formatting. the first
number
is 1000000009000001. If I enter that number as I have typed it here the
end
1 changes to a 0 and it does not increment correctly. I have tried
numeous
cell formats. Can I modify the formula for this item only and force in
the
extra 1

"Rick Rothstein" wrote:

Which formula are you using... the second one I posted (in my original
response to you) should return the check character itself rather than
the
check number. Here is that formula with the absolute reference problem
that
I mentioned in my other post fixed...

=MID("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%",
MOD(SUMPRODUCT(SEARCH(MID(A1,ROW($1:$99),1),
"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%") )-99,43),1)

As before, there is a single reference to A1 that needs to be changed
to the
address for the first cell containing your data. I just noticed there
is a
space in the encoding string at the 39th position. That means if your
check
number is 39, then the above formula will return a space which will be
"hard
to see". I have also manually broken the formula up in order to stop
your
newsreader from using the space character as a point to word-wrap at
(which
makes it possible for you, and others reading this thread, to
accidentally
erase it when combining the broken lines into a single line formula
when
placing it into the Formula Bar).

--
Rick (MVP - Excel)


"CLI-Art" wrote in message
...
Almost there. The formula seems to be working EXCEPT, it is not
replacing
numbers 10 and up with the corresponding alpha characters.

"Rick Rothstein" wrote:

First off, since you will probably want to copy the formula down the
column,
I left off a couple of needed absolute references. Use this formula
instead
of the one I posted originally...

=MOD(SUMPRODUCT(SEARCH(MID(A1,ROW($1:$99),1),"0123 456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-.$/+%")
)-99,43)

My formula assumes your text is in A1... you would put the above
formula
in
any other column (in most likely in row 1 of that column to keep the
text
and the MOD43 number in sync). If you have more text under A1 that
you
want
the MOD43 number for, then just copy my formula down through those
rows.
If
your text strings are in a different column, then change the A1
reference
in
my formula to the first cell in the column the text is in. For
example,
if
your first text string is in E3, then the above formula would become
this...

=MOD(SUMPRODUCT(SEARCH(MID(F3,ROW($1:$99),1),"0123 456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-.$/+%")
)-99,43)

which you might place in, say, F3.

--
Rick (MVP - Excel)


"CLI-Art" wrote in message
...
Perhaps I am not gettting this into my file correctly but it does
not
seem
to
be working correctly. Should I just copy the entire string into
the
first
cell and go from there?

"Rick Rothstein" wrote:

Does this formula do what you want?

=MOD(SUMPRODUCT(SEARCH(MID(A1,ROW(1:99),1),"012345 6789ABCDEFGHIJKLMNOPQRSTUVWXYZ-.
$/+%") )-99,43)

I think it calculates the MOD43 check number for the text in A1.
If
you
need
the formula to calculate the character equivalent to this number,
then
try
this formula...

=MID("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-.
$/+%",MOD(SUMPRODUCT(SEARCH(MID(A1,ROW(1:99),1),"012 3456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-.
$/+%") )-99,43),1)

--
Rick (MVP - Excel)


"CLI-Art" wrote in message
...
Is there a mod43 check digit calculator in Excel. If not, has
anyone
out
there made one?