Card Counting Calculator

If you're unfamiliar with card counting, see this intro by Antonio Zanutto, this step-by-step guide by Kevin Desprez, and this Judge Academy module by Mikaël Rabie. There are also some practice scenarios available here from Mikaël's card counting challenge project.

When card counting, the goal is to take some known pieces of information and use them to derive other, unknown pieces of information.

This is conceptually simple; the relationships between game values are governed by basic equations like "starting player turn number = natural card draws + 1 - starting hand size". But it can be hard to keep track of everything in your head, and in live situations it's important not to miss any details, so card counts end up being one of the more challenging investigative skills for judges to learn.

Normally this is handled by putting judges though a bunch of practice workshops to familiarize them with the process. But it's . Why do any hard work yourself when you could make Isaac a computer do it for you?


Enter the best information that you have available.The explanations provided below assume that you're taking no shortcuts, so a fetch land would be marked as "1 land removed from the battlefield", "1 extra land play", and "1 extra card removed from library". If you're an experienced card counter and know how the underlying math works, you can do the usual shortcuts of cancelling those out, and the calculator will still return the correct results. Numeric values support a minimum and maximum for situations where you can figure out a range but not the exact value.

If you need a specific piece of information, click on its name. The other fields that are most likely to be helpful will be highlighted in purple.

General game info

Active player:

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Card drawn for turn:

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Starting player:

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Land played this turn:

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Turn number:If a player has taken an extra turn, don't put that in the turn count, just treat it as though it were a spell that said "draw a card and you may play an extra land".

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Alice info

Mulligans:

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Cards removed from library:Remember to include any cards that got put back in later, such as by Endurance. Any cards that were brought into the game from outside the game, such as with Karn, the Great Creator or companion, should also be added both here and under the "extra cards removed from library" field. (These fields are actually counting how many cards entered a non-library game zone.) And if this is some strange format where something is making a player skip their draws for turn, you'll have to pretend those draws occurred and add them to this count.

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Extra cards removed from library:This is a count of all cards removed from Alice's library by any rule or effect other than the normal draws in the draw step. Divination, Flooded Strand, Demonic Tutor, etc. If cards were removed and then put right back, such as with Brainstorm or Green Sun's Zenith, you can have those cancel out and treat that as 0 cards removed.

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Lands controlled:

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Missed land drops:This counts prior turns only. If known that the player has not played a land on the current turn, mark that under "land played this turn" instead.

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Extra land plays:Includes both the game action of "playing an extra land", such as with Azusa, Lost but Seeking, and also lands put directly onto the battlefield such as with Arboreal Grazer. Remember that if the land is coming from the library, such as with Farseek or Courser of Kruphix, it needs to be added under the "extra cards removed from library" field as well.

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Lands removed from battlefield:Doesn't matter where they went from the battlefield, just that they left. Wasteland, Lotus Field, Daze, Simic Growth Chamber, etc. should all result in this count increasing. Note that if it was an effect that replaces a land on the battlefield with one from the library, such as Ghost Quarter or Flooded Strand, you'll also need to add 1 to the "extra land plays" and "extra cards removed from library" fields.

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Bob info

Mulligans:

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Cards removed from library:

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Extra cards removed from library:

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Lands controlled:

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Missed land drops:

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Extra land plays:

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Lands removed from battlefield:

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Color key:


It's my goal for this calculator to be a useful aid both for training and in live scenarios, where trying to keep track of everything in your head can be overwhelming. If you think of anything I could add or change that would make this calculator more helpful to you, please let me know.


With thanks to John Brian McCarthy for nerd-sniping me into spending a week doing nothing but working on this calculator.

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