Card Counting Resources: How to Count Cards in Blackjack, Honestly Explained

The most useful card counting resources start with an honest premise: counting can shift the odds in a blackjack game dealt from a shoe, but it does nothing in games that reshuffle every hand. Card counting means keeping track of which cards have already been dealt, so you know when the cards left in the shoe favour you. The best-known method, Hi-Lo, gives each card a value of +1, 0 or −1, and you add them up as the cards come out.

This guide explains how counting works, how to count cards with Hi-Lo step by step, why it fails online, where it's legal, and which resources to use next.

How does counting cards work?

Blackjack has memory. Unlike roulette, where every spin is independent, the cards dealt from a shoe don't go back in until the reshuffle. So the make-up of the remaining cards changes as the shoe is dealt.

A shoe that still holds lots of 10s and aces helps you in three ways:

• More blackjacks. You and the dealer get naturals equally often, but yours pay 3:2 and the dealer's only take your original bet.
• More dealer busts. The dealer must hit 12 to 16. A 10-rich shoe makes those hits bust more often.
• Better doubles. Doubling 10 or 11 works better when a 10-value card is more likely to arrive.

A shoe heavy in small cards does the opposite. Counting is just a way of telling the two situations apart without memorising every card.

Card counting basics: what's in a 6-deck shoe

A standard deck has 52 cards in 13 ranks. With 6 decks there are 312 cards, 24 of each rank. Hi-Lo splits them into three groups:

Because there are 120 low and 120 high cards, the count over a full shoe adds up to zero: (120 × +1) + (120 × −1) = 0. That's called a balanced count. A positive count partway through the shoe means more high cards than low cards are left.

Hi-Lo card counting, step by step

1. Learn perfect basic strategy first. Counting adds a small edge on top of correct play, so it's worthless if your play is wrong. Our blackjack strategy card has the full 6-deck chart.

2. Keep a running count. Start at 0 after a shuffle. For every card you see, add its tag: +1 for 2 to 6, 0 for 7 to 9, −1 for 10s and aces. Count every card dealt, including other players' cards and the dealer's.

Example: the first round shows 5, K, 3, 9, 2, A, 6. The tags are +1, −1, +1, 0, +1, −1, +1, so the running count is +2.

3. Convert it to a true count. A running count of +6 means more with one deck left than with five. Divide by the decks still to be dealt:

4. Size your bets by the true count. Counters bet the minimum when the true count is zero or negative and raise their bet as it climbs. The size of the increase is a bankroll decision, and bigger swings mean bigger risk.

5. (Advanced) Adjust some plays. Experienced counters change a handful of basic strategy decisions at high or low counts. Learn these only after steps 1 to 4 are automatic.

The edge a counter has to beat

Counting doesn't start from zero. It has to overcome the house edge you face when playing perfect basic strategy, and we measured that across 10 million hands per rule set:

These are Monte Carlo estimates with a standard error of about 0.036 percentage points each. We haven't simulated a card counter, so we don't publish a figure for how much counting gains. Two things follow from the table anyway:

• Rules matter before the count does. A 6:5 game starts 1.36 points deeper in the hole, and part of a counter's gain comes from 3:2 blackjacks in rich shoes, which 6:5 shrinks. Our 6 to 5 blackjack breakdown shows the full comparison.
• Penetration matters. Our simulation reshuffled after 75% of the shoe. The deeper a dealer goes before reshuffling, the more often the count reaches useful levels; if the reshuffle comes early, the count rarely moves far from zero.

Why counting is useless online when the deck is reshuffled

Some online blackjack games shuffle the virtual deck before every hand; others use continuous shuffling, where used cards go straight back in. In either case, counting can't work. The reason is simple:

• Counting relies on cards leaving the shoe and staying out until the reshuffle.
• If every hand starts from a full, freshly shuffled set of cards, nothing has left. The composition is identical every time.
• So the running count resets to zero every hand, and there's never a "rich" shoe to bet into.

That's not a sourced statistic; it follows directly from how counting works. The same logic applies to a physical table with a continuous shuffling machine.

Live dealer games are different, because they deal from a physical shoe. Whether counting is worth anything there depends on how deep the shoe is dealt and on the table's bet limits, and you rarely know the reshuffle point up front. Our live blackjack guide covers which rules to check.

Is card counting legal?

Counting cards in your head uses only information every player at the table can see.

• Nevada: card counting is legal, as Nevada Public Radio (KNPR) reported in January 2015, but casinos don't welcome it and may bar players they identify as counters.
• Nevada vs New Jersey: gambling law writer I. Nelson Rose explains that Nevada casinos may exclude counters, while New Jersey took a different path after the 1982 case Uston v. Resorts International.

Laws change and differ by country and state; these sources describe the situation as of their publication. Wherever you are, play only where gambling is legal and the operator is licensed, and respect a casino's decision if it asks you to stop.

Card counting resources we recommend

On our site:

• 6-deck basic strategy chart: the foundation every counter needs, with H17 and no-DAS changes.
• Blackjack strategy calculator: check the right play for any hand and rule set while you practise.
• Blackjack split rules and pair strategy: the pair decisions beginners most often miss.
• Our blackjack simulation results (CSV download): the house edge for every rule set we simulated.

Elsewhere:

• The Wizard of Odds strategy charts for 4 to 8 decks, which our charts follow, for S17 and H17 games.
• The KNPR report and I. Nelson Rose's column on counters, for the legal background.

All three are listed in the sources at the end of this page.

Playing blackjack with USDT: what counting means for crypto players

If you play blackjack online with USDT, find out how the game shuffles before you think about counting. If it reshuffles every hand, the right approach is basic strategy and table selection, nothing more.

Counting, where it works at all, needs a bankroll big enough to ride out long losing runs while you wait for good counts. That's a bigger commitment than the stake per hand suggests. If you want a game where every round is independent by design and you can verify each result, see how that works in our crypto dice game guide.

Common mistakes

• Learning to count before learning basic strategy.
• Using the running count instead of the true count in a multi-deck shoe.
• Trying to count an online game that reshuffles every hand.
• Believing counting is illegal everywhere, or that it's welcome everywhere.
• Treating counting as a guarantee. Even with an edge, short-term results swing widely.

More blackjack guides are on the blackjack hub.