Blackjack card counting means keeping track of the cards dealt so you can judge whether the remaining cards are richer in tens and aces or in low cards. It has a legendary reputation thanks to films and books, but in reality it is slow, careful bookkeeping with a small effect that depends entirely on how the cards are dealt.
This guide explains the basic Hi-Lo idea, the difference between running count and true count, and the conditions under which counting could matter at all. It also covers why counting does not help in RNG blackjack or at live tables that reshuffle constantly, and what is a more sensible approach: basic strategy. This is an explanation only.
In blackjack, cards that have been dealt are not returned to the shoe mid-game. When many low cards have come out, the remaining cards contain proportionally more tens and aces. That generally favours the player: blackjacks come more often and it is harder for the dealer to stay safely below 21.
Hi-Lo is the best-known and simplest counting system. Cards fall into three groups:
A low card leaving the shoe raises the count, because more high cards remain. A high card leaving lowers it. Sevens, eights and nines are ignored.
The running count starts at zero after a fresh shuffle. After every card you see, you add or subtract its value. If the cards 5, K, 3, 8 and 2 appear, the values are +1, −1, +1, 0 and +1, so the running count is +2.
The running count alone is not enough, because its meaning depends on how many decks are still left. A count of +4 with five decks remaining is minor. The same +4 with two decks remaining is much more significant. So the running count is divided by the number of decks remaining, giving the true count.
Example: the running count is +6 and about three decks remain in the shoe. The true count is 6 divided by 3, or +2. The higher the true count, the more high cards remain in proportion.
Counting produces an effect only when three conditions hold at the same time:
If any one of these is missing, the effect disappears. Counting does not make a game favourable by itself. It only shifts the player's expectation slightly during a small share of the rounds, typically by around about a percentage point, and short-term variance is many times larger. No method removes the house edge, and counting promises nothing in any session.
Online blackjack against the computer runs on a random number generator (RNG). Typically every round is dealt from a fresh, fully shuffled deck or shoe. The previous round has no effect on the next one.
It follows directly that the running count is always zero at the start of every round. There is no accumulated information to use. Games such as Blackjack Single Hand (Gaming Corps, RTP 99.73%), Blackjack Classic (NetEnt, RTP 99.65%) and American Blackjack (Habanero, RTP 99.65%) work on this principle. In them, the right tool is basic strategy, not counting.
At a live table a real dealer deals real cards, so counting may seem more plausible at first glance. In practice, the structure of live blackjack still makes it a poor fit:
Live blackjack is still a good choice if you like a real dealer and the table atmosphere. You will find options in the live blackjack category, for example Ezugi's Gold Blackjack 5 (RTP 99.67%) and Blackjack Salon Prive (RTP 99.67%). Their RTP figures come from the rules of the game, not from counting.
Basic strategy is a mathematically derived table that gives the statistically strongest action for every hand against every dealer upcard: hit, stand, double down or split. It is based on which decisions lose the least over the long run, and it works at any table regardless of whether the shoe has just been shuffled.
Basic strategy does not remove the house edge either. It only reduces it to the minimum possible under the rules in play. It is covered in more detail in our blackjack strategy guide, and the rules of the game are in the blackjack rules guide.
It matters more to check the table rules and RTP than to count cards. A 3:2 blackjack payout versus 6:5 changes the house edge noticeably, as does whether the dealer hits soft 17. Blackjack RTP values in the catalogue are generally near 99%: Quantum Blackjack Plus Instant Play (Playtech) is 99.68% and Multihand Blackjack (Pragmatic Play) is 99.62%.
Blackjack is one of the games with the lowest house edge, but the edge is still there. Set a budget before you start and take breaks. If playing starts to feel compulsive, seek help.
It means tracking dealt cards with a simple point system to judge whether the remaining cards contain proportionally more high or low cards. It does not predict any individual card.
Cards 2 to 6 are +1, cards 7 to 9 are 0 and cards 10 to ace are −1. You add the values round by round to get the running count, then divide it by the decks remaining to get the true count.
The running count is the sum of all dealt card values. The true count is that sum divided by the number of decks remaining, so it reflects the situation regardless of shoe size.
No. Each round is dealt from a freshly shuffled deck or shoe, so the running count is always zero at the start of a round.
In practice no. Many live tables reshuffle early or use a continuous shuffler, so there is no accumulated information, and the pace is fast.
Basic strategy. It gives the statistically strongest action in each situation and works at every table, though it does not remove the house edge.
No. Counting changes the odds only slightly and only under specific conditions, and short-term results vary widely. No method removes the house edge.