Does it teach card counting?

twentyone focuses on basic strategy: the mathematically correct play for every hand. That's the foundation that cuts the house edge to its minimum. Counting drills are on the roadmap, but mastering basic strategy comes first.

Will the strategy match my casino's rules?

That's the point of the rules panel. Set the deck count, soft-17 rule, double-after-split, surrender, and payout to match your table, and the correct strategy grid recalculates to fit those exact conditions.

Does it work on my phone?

Fully. The table, grids, and coach are responsive and built to be practiced one-handed on mobile or full-screen on desktop.

Train smarter, not your luck

Stop guessing.
Play perfect blackjack.

twentyone is a practice table that drills basic strategy into muscle memory. Real rules, real odds, and a coach that catches every mistake the moment you make it.

Deal me in. It's free See the strategy grid

−0.5%

House edge at perfect play

2 min

To your first trained hand

100%

Free · no chips to buy

Blackjack pays 3 to 2 · Dealer stands on all 17

♦

Stand.Dealer shows 6. Let them bust. Hitting 13 here loses 0.9% EV.

Dealer · shows 6

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♣

♥

You · hard 13

Your table, your rules

Configure the exact game you'll sit down to.

Strategy changes with the rules. Set the shoe up to match your casino and the trainer recalculates the correct play for every hand instantly.

Full rules guide

⚙Table rules

Vegas Strip

Decks in shoeMore decks, slightly higher house edge

Dealer on soft 17Hit (H17) vs. Stand (S17)

Double after splitDAS allowed

SurrenderLate surrender available

Blackjack payout

♠

Eight rule sets that actually matter

Deck count, soft 17, DAS, re-splits, surrender, peek, payout, and penetration. The variables that move the edge.

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Strategy recomputes live

Switch from S17 to H17 and watch the correct grid update. You're never memorizing the wrong chart.

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Save your home table

Match the casino you actually play and keep practicing against those exact conditions.

Probability, made readable

The whole basic-strategy chart, colour-coded.

Every cell is the mathematically optimal move for your hand against the dealer's upcard. Study it, then prove you've learned it at the table.

Open the full strategy chart

Hard totals · dealer upcard

HardSoftPairs

	2	3	4	5	6	7	8	9	10	A
17+	S	S	S	S	S	S	S	S	S	S
16	S	S	S	S	S	H	H	H	H	H
15	S	S	S	S	S	H	H	H	H	H
13–14	S	S	S	S	S	H	H	H	H	H
12	H	H	S	S	S	H	H	H	H	H
11	D	D	D	D	D	D	D	D	D	H
10	D	D	D	D	D	D	D	D	H	H
9	H	D	D	D	D	H	H	H	H	H
8–	H	H	H	H	H	H	H	H	H	H

Stand Hit Double Split

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Hard, soft & pairs in one place

Flip between all three charts. The grid always reflects the rules you configured, not a generic textbook.

See the odds behind the cell

Tap any square for the expected value of every option, so you understand why the play is right.

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From reference to reflex

Practice mode quizzes you on weak spots until the chart lives in your head, not on your screen.

An expert over your shoulder

A coach that catches the wrong move, instantly.

The moment you deviate from optimal play, twentyone flags it, shows you the better line, and explains the math. Mistakes become lessons, not losses.

Live feedback · this hand

You hit on hard 13 −0.9% EV

Against a dealer 6, that's a costly draw. The dealer busts here more than 4 in 10 times.

✓

Correct play: Stand best line

Let the weak upcard work against the house. Standing wins this spot far more often than hitting.

Session accuracy · 92%Streak · 14 correct

Build the instinct, not just the knowledge.

Reading a chart is easy. Recalling it under pressure isn't. The coach turns every hand into deliberate practice.

✓ Instant right/wrong call on every decision

✓ Plain-English reason behind the optimal play

✓ Expected-value cost of each mistake

✓Accuracy & streak tracking across sessions

✓ Optional silent mode for self-testing

Sit down. Get dealt in. Get better.

No sign-up wall, no chips to buy. Just you, the felt, and a coach that won't let a mistake slide.

Open the table Browse strategy first

Good to know

Questions, answered.

Yes. The trainer, the configurable table, the strategy grids, and the in-game coach are all free. There are no chips to buy and nothing to wager. It's a practice tool, not a gambling app.

Stop guessing.Play perfect blackjack.