In Excel, we have a number set for the columns as such:

A , B , C, ..., Z, AA, ...

Is there a name for this "numbering" set? Such as hexadecimal for base-16, or binary for base-2? Or just natural numbers for base-10

  • 1
    Er... alphabetical? Why does that not work?
    – Andrew Leach
    Sep 6, 2016 at 20:32
  • Is that really the term...? I can't seem to find anything on it. I mean I don't mind just making up a name I guess, but if one exists...
    – Nick Bull
    Sep 6, 2016 at 20:34
  • I doubt the ancient Greeks or Romans would have had a word for base 26 counting - I don't think either of them had 26 letters in their alphabet anyway. But some enterprising scholar here might be able to come up with a latter-day coinage. Sep 6, 2016 at 20:34
  • Base 26 numbering or should it be lettering? Sep 6, 2016 at 20:37
  • 2
    It's not just base-26 counting, it is zero-free base-26 counting.
    – cobaltduck
    Sep 6, 2016 at 21:03

1 Answer 1


Apparently it's called the bijective base-26 system. It is a base-26 numeral system where the 26 letters of alphabet are used as the symbols for values 1-26 (there is no zero in this system).

AFAICT, the bijective qualifier indicates that no leading/trailing zeros are permitted or possible.

If you're looking for the equivalent of binary, decimal, hexadecimal etc. for base-26, it would be hexavigesimal.

  • Bijective in this case means every positive integer has exactly one representation. The fact that no leading zeros are allowed is a consequence of this. Sep 7, 2016 at 4:16
  • This is an awesome answer! Not quite as pleasing as if hoped but I guess for the criteria I can't expect much more. Thanks!
    – Nick Bull
    Sep 7, 2016 at 10:52

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