I haven't dusted any of my duplicate cards in a while. I have quite a few common cards that show a count of "9+".

Is there a maximum number of copies of a card? What happens when I hit that maximum, is the card auto-dusted or is it just lost?

2 Answers 2


As there is not offical statement on the card limits, at worst there would be some programming related limit.

At the very worst this number of cards would be stored in and signed 8-bit number variable, putting the maximum number of cards at 127.

Most likely the number is at least 8-bit unsigned integer (because you can't have negative amount of cards), putting the maximum at 255.

16-bit integer is also possible, when the maximum would be 32,767 or 65,535 (depending on wether the number is signed or not). But then Blizzard would need double the space to store people's collections.

In short, unless you think you have literaly hundreds of copies of a given card, you shouldn't have to worry.

(Assuming Blizzard isn't doing something incredibly fancy trickery, but that would be impossible to speculate any limits on.)

  • 4
    As an aside, Blizzard uses (or at least, originally used) signed 32 bit integers for card attack and health values. It's possible that they used the same data type for card counts.
    – two bugs
    Commented Sep 4, 2015 at 12:29
  • 12
    Actually, I take that back. Lets say they are prepared for 200 million users (current number is about 75 million) and 1000 cards (currently about 500?). If the number of cards is stored in 32 bits, the database would be about 1 terabyte, including some space for overhead. This is peanuts, when it comes to databases, for a company like Blizzard.
    – DJ Pirtu
    Commented Sep 4, 2015 at 12:56
  • 6
    I would bet money that these are stored in a 32 bit, or even 64 bit, integer. Storage is incredibly cheap, changing schema and assumptions is not.
    – jaredready
    Commented Sep 4, 2015 at 14:09
  • 4
    @Zaibis I'd take that more as a gentle nudge towards "You know, you don't really need this many of these. As in, ever. At all."
    – DJ Pirtu
    Commented Sep 4, 2015 at 15:17
  • 6
    @Zaibis "9+" is two characters long. By fixing the length of displayed characters, some layout assumptions can be made in the UI.
    – Amy B
    Commented Sep 4, 2015 at 19:54

No. I've seen plenty of streamers getting 9+ cards and they've kept opening cards.

Blizzard hasn't mentioned anything about a card cap either, so you're safe.

  • 4
    There is likely a (realistically unreachable) cap at the limit of the data type they use to represent it. This would likely be 2^31, 2^32, 2^63 or 2^64 (minus one, since the zero is included), depending on if they use signed/unsigned int/long... OR it could be something totally different. Anyway, your answer covers all realistic situations, +1.
    – Svj0hn
    Commented Sep 4, 2015 at 12:14
  • 1
    Just because Blizzard hasn't mentioned a card cap (you know of) doesn't mean that there is none.
    – Philipp
    Commented Sep 4, 2015 at 16:46
  • That is true, however, it most likely means that there is not a limit that is reachable in the near future. Commented Sep 4, 2015 at 16:47
  • We thought that Steam Monster Summer Game didn't have a limit. And guess what, 100m. But yeah, john is correct.
    – ave
    Commented Sep 5, 2015 at 9:00

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