Hi-Lo: The Default Counting System

The balanced Level-1 count most card counters learn first. Tag values, running-count mechanics, conversion, and the performance numbers that make it the default.

What It Is

Hi-Lo is a balanced Level-1 counting system: every card is assigned a tag of +1, 0, or −1, and the tags sum to zero across a full deck. As cards come out, the player tracks a running sum (the running count) that trends positive when the deck is rich in tens and aces, and negative when the deck is rich in low cards.

It was published by Harvey Dubner in 1963 and refined by Edward Thorp, Julian Braun, and Stanford Wong in the years that followed. It's the system almost every blackjack book uses as the teaching example, and the system most pros actually play.

The Tag Values

Cards	Tag	Why
2, 3, 4, 5, 6	+1	Low cards leaving the deck are good for the player — the remaining shoe is richer in tens.
7, 8, 9	0	Neutral. These cards neither favor nor hurt the player noticeably when removed.
10, J, Q, K, A	−1	High cards leaving the deck hurt the player — the remaining shoe is weaker.

Because the tags sum to zero across a 52-card deck (5 × 4 × (+1) + 3 × 4 × 0 + 5 × 4 × (−1) = 0), the count is balanced. Balanced counts are slightly more accurate than unbalanced alternatives like KO, at the cost of requiring a conversion before using for bets or deviations.

From Running Count to True Count

A running count of +6 means something different in a shoe with five decks left than in a shoe with one deck left. The same +6 is much more concentrated (and therefore more valuable to the player) when fewer cards remain. True-count conversion normalizes:

True Count = Running Count ÷ Decks Remaining

Decks remaining is estimated by eye from the discard tray. Most players round to the nearest half-deck. With a running count of +6 and two decks remaining, the true count is +3 — high enough to justify a significantly larger bet and to trigger most of the deviations.

Performance Numbers

Hi-Lo is judged by three numbers (all from Peter Griffin's Theory of Blackjack):

: 0.97. Near-perfect — the count tracks EV almost as well as a point-count system can.
: 0.51. Middle of the pack. Stronger systems (Hi-Opt II, Zen) score higher because they weight tens and aces differently; Hi-Lo collapses them.
Insurance correlation: 0.76. Good enough that insurance becomes a profitable bet at true count +3 or higher.

The tradeoff: Hi-Lo is weaker on playing efficiency than multi-level systems but much easier to run accurately at casino speed. For shoe games (where bet sizing contributes most of the EV), Hi-Lo's near-perfect betting correlation is what matters — which is why it remains the default despite the availability of stronger alternatives.

Learning Progression

The typical path: memorize tag values (an afternoon), drill single-deck counting at home until you can count down a deck in under 25 seconds without error, then add drills so the count runs in the background while you play correctly. Add the only after counting is automatic — deviations on top of an error-prone count is worse than basic strategy alone.

Practice Hi-Lo against live dealt hands.
Configure the simulator with Hi-Lo counting on and drill running-count accuracy in real conditions.

Run Simulation →