The 21 Card Trick
Somebody chooses one of 21 dealt cards, in 3 piles of 7. You deal them into three piles twice more, asking only which pile it is in — never which card, and you find their card.
Deal it through
Be the spectator and the page does the trick to you. Be the magician and you deal all twenty-one yourself.
As the spectator you think of one of the cards and tell it which pile. That is all it ever learns, exactly as it would across a table. As the magician the roles swap: it thinks of a card, and you deal every one of the twenty-one yourself. The gold rings are then the cards still possible — twenty-one, then seven, then two or three, then theirs — so you can see the method while you practice. It stops you the moment you put a card where it cannot go.
There is no sleight of hand in it. There is barely any handling. The deal does the work.
Also called the Eleven Card Trick, the three pile card trick, the 21 card magic trick, or just that one everybody does. It is a card trick with 21 cards and three piles, and the deal does every part of it. It is also the most performed self-working card trick there is, and the one most often performed badly — the method is easy and the presentation is where it lives or dies.
How to perform the 21 card trick, step by step
- Count off twenty-one cards. Any twenty-one. Let them shuffle first if they want to — it makes no difference at all.
- Deal three face-up piles, across. One card to the left pile, one to the middle, one to the right, and round again until all twenty-one are down. Across, not one pile at a time. Deal down the piles instead of across them and you ruin the trick. It is the commonest way people do.
- Ask which pile. "Don't tell me the card. Just tell me which of these three it's in." They point.
- Gather, and put their pile somewhere you can repeat. Use the middle. Pick up one of the other two, drop their pile on it, drop the last pile on top. Their seven now sit in the middle of the twenty-one. On top or underneath work just as well — what the trick cannot survive is changing where you put it.
- Deal and ask a second time, and gather it the same way. Same means same. Their pile in the middle again if that is what you did first; on top again if that is what you did first. This is the step people get wrong, because putting it in the middle once feels like enough.
- Deal a third time and ask a third time. Their card is now in a fixed place in the pile they name, and which place depends only on how you have been gathering:
| If you put their pile… | Their card is |
|---|---|
| in the middle, both times | the 4th of 7 — the middle card |
| on top, both times | the 1st — the top card |
| underneath, both times | the 7th — the bottom card |
If you would rather count down to the 11th card
If you have been gathering in the middle, gather that third time as well — their pile in the middle again, and their card is the eleventh of the twenty-one. That is the version most people are taught, and it is the same fact wearing a different coat — the eleventh of twenty-one is the fourth of the middle seven. Take it if your presentation wants a count, a spell, or a deal to a number. Otherwise the middle card of the named pile is fewer moves and nothing to remember.
The only two things that can go wrong
You dealt down instead of across, or you gathered their pile into a different place the second time than you did the first. Both produce a card that is not theirs and no way to recover in the moment. If you are learning this, deal the rounds slowly and out loud until the pattern is automatic, which, incidentally, is what performing it in the demo above is for.
Why does the 21 card trick work?
Dealing across three piles cuts the possibilities to a third each time. Gathering with their pile in the middle lands them in the same place, every time.
Follow one card. After a deal, their pile holds seven cards. You put those seven in the middle of twenty-one, so their card is somewhere between position 8 and position 14. Deal across again. Those seven cards spread through the piles, and the middle seven now sit between positions 8 and 14 of a range that was already only seven wide. Three rounds of that and the range has collapsed to a single position.
| After | Where their card could be | Possible |
|---|---|---|
| You count off 21 | anywhere | 21 |
| First gather | positions 8–14 | 7 |
| Second gather | positions 10–12 | 2 or 3 |
| Third gather | position 11 | 1 |
Why is it always the middle card of the last pile?
This is the part worth knowing, and most write-ups skip it.
After two deals their card is at position 10, 11 or 12 — never anywhere else. Deal those three positions across three piles and watch where they go. Position 10 starts a new round of three, so it lands in pile one. 11 goes to pile two, 12 to pile three. Three candidates, three different piles. That is why the third answer can only ever leave one of them standing.
Each of those three is the fourth card into its pile, because positions 10, 11, and 12 come after you have dealt nine cards — three to each pile. So whichever pile they name, their card is the fourth of seven: the middle. It cannot be otherwise, and it does not depend on a single thing they said earlier.
| Deal | Where their card sits in the pile they name |
|---|---|
| First | anywhere — 1st to 7th |
| Second | 3rd, 4th or 5th |
| Third | always the 4th — the middle |
Why does the chosen pile have to go in the middle?
It does not. This is where nearly every write-up of this trick, including an earlier version of this page, says something untrue.
The trick needs one thing. You place their pile the same way every time. Put it on top every round and their card finishes on top of the pile they finally name. Put it underneath every round and it finishes at the bottom of that pile. Put it in the middle every round and it finishes fourth of seven. All three work.
What breaks it is changing your mind. Place their pile on top once and in the middle the next, and their card can finish in either of two places.
Two places is a guess. A guess is the one thing this trick exists to avoid.
| How you place their pile | Where their card finishes in the pile they name |
|---|---|
| On top, both times | 1st of 7 — always |
| In the middle, both times | 4th of 7 — always |
| Underneath, both times | 7th of 7 — always |
| Any two that differ | two possible positions — a guess |
Why three deals and not two?
Each deal cuts the possibilities by roughly a third: 21, then 7, then two or three, then one. Two deals leave you with a small handful, which is a guess. The third works because those last two or three cards always sit at positions 10, 11, and 12, which the next deal sends to three different piles. Whichever pile they point at, exactly one survives, and it lands on eleven. A fourth deal would change nothing, which an audience feels even when they cannot say why.
Is the 21 card trick the same as the card game 21?
No. The card game called twenty-one is blackjack, where you try to reach a total of 21. This is a magic trick that uses twenty-one cards, dealt into three rows of seven. They share the number and nothing else.
Does the 21 card trick work with other numbers of cards?
Yes, and with far more of them than the cubes. A packet settles whenever it is within one of an odd multiple of three, so 20, 21, and 22 all work while 23, 24, and 25 do not. The card finishes in the middle of the packet, rounding up, after as many deals as it takes to divide down by thirds. Twenty-seven lands on the fourteenth in three deals, nine lands on the fifth in two, and the whole fifty-two lands on the twenty-seventh in four. The calculator above deals any size through and tells you.
Doing it with a different number of cards
Twenty-one is not special, and it is not the only packet that works. Pick a size below and this works out whether the trick settles, how many deals it takes, and which card from the top theirs will be — by dealing that packet through from every position their card could start in.
How many cards have you got?
Every size from 3 to 52. The lit ones settle on a single card.
The rule, and why the sizes come in threes
A packet settles when it is within one of an odd multiple of three. So 20, 21, and 22 all work, and 23, 24, and 25 do not. The next three that work are 26, 27, and 28.
It takes as many deals as it takes to divide the packet down to one card by thirds — one deal up to 3 cards, two up to 9, three up to 27, and four up to 81. And the card always finishes in the middle of the packet, rounding up: eleventh of twenty-one, fourteenth of twenty-seven, eighth of fifteen.
Two consequences worth having. The whole deck works. Fifty-two cards, four deals, and their card is the twenty-seventh — no counting out a packet first, which removes the most suspicious thing you do. And a size that does not settle is not chaos: it leaves the card in exactly two adjacent positions, never more, so nineteen cards still narrows the deck to a pair.
Making it fool anybody over the age of nine
Nearly everyone has seen this. That is not the problem it appears to be — what people have seen is the procedure, and what makes it play is everything around the procedure.
- Never deal three times the same way. Deal face up, then face down, then face up. The rhythm changing hides the fact that the structure did not.
- Do not count in front of them. Counting is the moment the method shows, which is the real reason to take the card from the middle of the last pile instead. You already know which card it is before you touch it, so you can look at them rather than at your hands.
- Give them the shuffle. It costs nothing and it removes the only objection they have.
More
The 27 card trick is this one grown up: three piles again, but three deals put their card at any position you name, because 27 is three cubed. If you like why this one works, that is the one to read next.
The Si Stebbins stack is the opposite kind of trick: set the deck first, and the arithmetic does the rest.
Harrison Alley
Hobbyist · Writes Sleightless
A hobbyist, not a professional. I write up the self-working end of card magic, because it is the door I would point a beginner at, and every trainer here is played through and checked before it ships.