How to Count Cards in Blackjack

Card counting keeps track of the high and low cards already dealt, so you know when the cards still in the shoe favour you. Learn the Hi-Lo count, practise it with three drills, and see what each count is really worth.

+1 · 0 · −1Hi-Lo values for 2–6, 7–9 and 10–A

≈ +0.5%Your edge gained per point of true count

800MSimulated rounds behind our figures

Show the count

Cards are dealt one at a time from a shuffled deck. Keep the running count in your head: every so often the dealing stops and you're asked for it.

How to count cards: the Hi-Lo system

A balanced count: every card gets one of three values, you only ever add or subtract 1, and a full deck adds up to 0.

Give every card a value

2, 3, 4, 5 and 6 count +1. 7, 8 and 9 count 0. 10s, face cards and aces count −1.

Keep a running count

Start at 0 after the shuffle and add the value of every card you see: yours, the other players’ and the dealer’s.

Convert to the true count

Divide the running count by the decks still to be dealt. A running count of +6 with 3 decks left is a true count of +2.

Bet with the count

Bet the minimum when the true count is +1 or lower, and more as it rises. Take insurance only at +3 or higher.

Cards	Hi-Lo value	Why
2, 3, 4, 5, 6	+1	Low cards help the dealer, who must draw to 17. Fewer of them left is good for you.
7, 8, 9	0	Neutral: they change little either way.
10, J, Q, K, A	−1	Tens and aces make blackjacks (paid 3 to 2 to you) and bust the dealer's stiff hands. More of them left is good for you.

A full deck adds up to 0, which is why the last card of the “Count a deck” drill can be named from the count.

What each true count is worth

From 800 million simulated rounds of six-deck blackjack: dealer hits soft 17, double after split, no surrender, blackjack pays 3 to 2, reshuffle after 4.5 decks, basic strategy and the same bet every round.

True count	Share of rounds	Your edge	Dealer aces with a ten under
−3 or less	15.5%	−2.68%	27.9%
−2	12.4%	−1.34%	29.6%
−1	19.0%	−0.85%	30.4%
0	26.6%	−0.39%	31.1%
+1	11.8%	+0.19%	31.9%
+2	6.5%	+0.68%	32.6%
+3	3.7%	+1.17%	33.3%
+4	2.1%	+1.58%	34.1%
+5	1.2%	+1.99%	35.0%
+6 or more	1.4%	+2.77%	36.5%

True count rounded down: +2 means from +2.0 up to +2.9. Across all counts, betting the same every round loses 0.64% of what you stake. Insurance pays when more than a third of dealer aces hide a ten.

Try a bet spread

Set how many units you'd bet at each true count and see the long-run result, using the simulated edges above.

True count 0 or lessTrue count +1True count +2True count +3True count +4True count +5 or moreOne unit is

Bets in units. Enter 0 to sit out those rounds (watch without betting). This spread: 1 to 12.

+0.44Units won per 100 rounds, on average (4.42)

±29.4Typical swing over 100 rounds, in units (±294.05)

+0.28%Your edge on all money bet

442,928Rounds before the average win outweighs a typical swing

Card counting: what it can and can't do

What it can do

Tell you when the cards left in the shoe favour you, so you can bet more then and less the rest of the time. It also tells you when insurance is worth taking.

What it can't do

Win every session or work everywhere. The edge is small next to the swings, most software blackjack reshuffles every round, and casinos can shuffle early or limit your bets if they think you're counting.

Questions

Does card counting actually work?

Yes, in games dealt from a shoe that isn't reshuffled after every round. In our simulation of 800 million rounds of six-deck blackjack, the player's edge went from −0.39% at a true count of 0 to +1.17% at +3 and +1.99% at +5. High counts are rare, though: the count was +2 or more in only 14.8% of rounds, so the profit comes from betting more at those moments.

How do you count cards in blackjack?

With the Hi-Lo count: add 1 for every 2, 3, 4, 5 and 6 you see, subtract 1 for every 10, face card and ace, and ignore 7, 8 and 9. Keep that running count from the shuffle, divide it by the number of decks left to get the true count, and bet more when the true count is high.

What true count should you raise your bet at?

In our six-deck game the edge turned in the player's favour at +1 (+0.19%) and grew by about half a percent for every point after that (+0.68% at +2, +1.17% at +3). A common approach is to bet the minimum up to +1 and raise it from +2.

When should you take insurance?

Insurance pays 2 to 1, so it breaks even when a third of dealer aces have a ten underneath. In our simulation that happened at a true count of +3 (33.3% of aces) and above it insurance wins money. Below +3, turn it down.

How much can you win counting cards?

Less than most people expect. Betting 1 unit up to +1, then 2, 4, 8 and 12 units at +2, +3, +4 and +5 or more won about 0.44 units per 100 rounds in our simulation, while a typical swing over those 100 rounds was about 29 units either way. Try other spreads in the calculator above.

Can you count cards at online blackjack?

Not at most software (RNG) blackjack games: they shuffle the virtual cards before every round, so nothing you saw carries over. Many live dealer tables deal from a real shoe, but how deep the dealer goes before the reshuffle decides how often the count gets high enough to matter.

Is card counting illegal?

Counting in your head isn’t cheating: you only use cards everyone at the table can see. Casinos can still respond, by shuffling early, limiting your bets or asking you to stop playing blackjack. Using a device to keep track of cards is a crime in Nevada (NRS 465.075).

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