The Hi-Lo Card Counting System

Hi-Lo (also written High-Low) is the most popular card counting system in blackjack, and the one almost every counter learns first. It is a simple, balanced, single-level count that captures most of the edge available from counting while staying easy enough to run accurately at a real table.

The Hi-Lo card values

The Hi-Lo system assigns +1 to low cards, 0 to middle cards, and −1 to high cards. You track a single running total of these values as cards are dealt.

+1: 2, 3, 4, 5, 6
0: 7, 8, 9
−1: 10, J, Q, K, A

The logic mirrors how cards affect the game. Removing low cards from the shoe is good for the player (it leaves a high-card-rich deck), so they are +1. Removing high cards is bad for the player, so they are −1. The 7, 8 and 9 are close to neutral and are ignored.

Why Hi-Lo is a balanced count

A standard 52-card deck has twenty cards worth +1 (four each of 2, 3, 4, 5, 6) and twenty worth −1 (sixteen ten-value cards plus four Aces). Because the positives and negatives are equal, a perfectly counted full deck always ends on 0. That property is what makes Hi-Lo a balanced system — and it is exactly why you must convert the running count to a true count by dividing by decks remaining.

From running count to true count

Keep your running count as the raw sum, then convert to the true count for any decision:

True count = running count ÷ decks remaining

With a +8 running count and four decks left, the true count is +2. The true count normalizes the signal so it means the same thing at any point in the shoe. See the step-by-step guide for the full procedure.

Betting correlation and playing efficiency

Two numbers describe how good a counting system is:

Betting correlation (BC) — how well the count predicts when to raise your bet. Hi-Lo scores about 0.97, near the maximum. Since most of a counter’s profit comes from betting, this is the number that matters most.
Playing efficiency (PE) — how well the count guides strategy deviations. Hi-Lo is about 0.51, which is more modest. Because Hi-Lo treats the Ace as a high card for betting but the Ace is less relevant for playing decisions, some advanced players keep a separate side count of Aces to improve accuracy.

For nearly all players the trade-off lands firmly in Hi-Lo’s favor: a simple, accurate count beats a complex one you make mistakes with.

A worked example

Suppose six hands are dealt and you see: 4, 10, 6, K, 2, 5, 9, A, 3, 7, Q, 8.

Counting in order: +1, −1, +1, −1, +1, +1, 0, −1, +1, 0, −1, 0. The running count is +2. If roughly five decks remain in the shoe, the true count is about +0.4 — barely positive, so you would still bet near the minimum. The count has to climb meaningfully before you raise your bet. Practice this for free on our blackjack games.

Frequently asked questions

What are the card values in the Hi-Lo system?

In Hi-Lo, cards 2 through 6 count as +1, cards 7 through 9 count as 0, and 10s, face cards and Aces count as -1. These values add up to zero across a full deck, which makes Hi-Lo a balanced counting system.

Why is Hi-Lo called a balanced count?

There are twenty +1 cards (four each of 2-6) and twenty -1 cards (sixteen tens plus four Aces) in a 52-card deck, with the 7s, 8s and 9s neutral. Because the pluses and minuses are equal, counting down a complete deck always returns to zero. Balanced systems require dividing by decks remaining to get a true count.

Is Hi-Lo the best card counting system?

Hi-Lo is the best system for almost everyone. It captures the large majority of the available edge, is simple enough to run accurately at speed, and is the most documented system. More advanced multi-level counts gain only a little extra and are much harder to keep error-free.

What is betting correlation and playing efficiency?

Betting correlation measures how well a count predicts when to raise your bet; Hi-Lo scores about 0.97 out of 1, which is excellent. Playing efficiency measures how well it guides strategy deviations; Hi-Lo is around 0.51, which is lower, which is why advanced players sometimes keep a separate side count of Aces.