The Hi-Lo Card Counting System

Hi-Lo is the most widely used card counting system in blackjack, and it has held that spot for decades because nothing else matches its power-to-effort ratio. One level of tags, one running count, one conversion to a true count — that is the whole engine. If you are brand new to counting, start with the overview in how to count cards. This page digs into Hi-Lo itself: the values, the drills, the benchmarks, and how it stacks up against KO and Hi-Opt II.

The tag values — and why they are what they are

Hi-Lo assigns every card one of three tags:

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

The logic is about who benefits from what remains in the shoe. High cards work for the player: a shoe rich in tens and aces produces more blackjacks (which pay you 3:2, while a dealer blackjack only wins your bet), lands your double downs more often, and busts the dealer more often when the rules force a hit on a stiff hand. Low cards do the opposite — they rescue the dealer's 12 through 16.

So when low cards leave the shoe, the count climbs and what remains is ten-and-ace rich — good for you. When high cards leave, the count falls and the leftover shoe favors the dealer. The running count is literally a measure of how much richness is left.

Balanced by design: a full deck counts to zero

Count through all 52 cards and the tags cancel exactly: twenty +1 cards (2–6), twenty −1 cards (sixteen ten-values plus four aces), and twelve zeros. The sum is 0. That makes Hi-Lo a balanced count, and the property matters twice.

First, it gives you a built-in accuracy check — the full-deck runout drill below must end on exactly 0. Second, it is what lets a running count be converted into a true count: running count divided by decks remaining. Because the neutral point of a balanced count is always zero, "zero" means "neutral shoe" no matter how deep into the shoe you are. Floor or round the division consistently — our trainer floors it for the bet ramp.

What the count is worth

Each true count point shifts the edge roughly +0.5% toward the player. Perfect basic strategy alone plays at about −0.5% (rules-dependent), so around TC +1 the game is close to even, and above that you are the favorite. Played with a proper bet spread on a good 3:2 shoe game, Hi-Lo delivers roughly +0.5% to +1.5% over the house.

Our trainer's default ramp: TC +1 or less, bet 1 unit; +2, 2 units; +3, 4 units; +4, 8 units; +5 or more, 12 units. One non-negotiable: never play 6:5 blackjack. The short payout adds about 1.4% to the house edge and makes counting effectively worthless.

The three core drills

1. Single-card tags. Flip one card at a time and say its tag instantly. The goal is recognition, not arithmetic — you should see a 5 and think "+1" the way you see a red light and think "stop."
2. Pair cancellation. Deal cards two at a time. A high card and a low card cancel to zero — skip the pair entirely and move on. Real-table speed comes almost entirely from cancelling; strong counters process most of a round as pairs and only add the leftovers.
3. Full-deck runout. Count down an entire 52-card deck. Because Hi-Lo is balanced, you must finish on exactly 0. Any other number means you miscounted somewhere — reshuffle and go again.

You can run all of this against a dealing engine on our free counting trainer, which tracks your count and shows live EV as you play.

Speed benchmarks

The benchmark that matters is the table itself: you need to hold a perfect count at the speed a real dealer deals, with conversation, betting, and chip handling all competing for attention. Run the full-deck drill until a flawless count is routine, then keep pushing the pace until the count survives dealing speed. Respect the order, though: accuracy first, speed second. A fast wrong count loses money more efficiently than no count at all, because it tells you to raise bets at exactly the wrong moments.

Why counts go wrong

• Hesitating on 7, 8, 9. Zero-tag cards should be invisible. If they cost you a beat, drill them until they don't.
• Missed cards on the pickup. Dealers scoop busted hands fast. Count cards as they appear, not at the end of the round.
• Sign flips near zero. Crossing between positive and negative territory is where counts silently invert. Say the sign in your head, not just the number.
• Dropping the count while multitasking. Talking, betting, dividing for the true count — anything that shares headspace. Drilling makes the count automatic so there is headspace left to share.
• Double-counting your own hand. Count each card once, the first time you see it, and never again.

Hi-Lo vs KO vs Hi-Opt II

KO's pitch is simplicity in play: because it is unbalanced — a full deck does not sum to zero — it is built to run on the running count alone, with no true-count division. The cost is coarser bet sizing. Hi-Opt II sits at the other extreme: a multi-level count with a required ace side count that buys extra playing accuracy at the price of real work on every hand. Hi-Lo is the sweet spot between them, which is why it remains the default recommendation and the system our trainer teaches.

After you own the count

The count does more than size bets. Insurance — normally a losing bet — becomes profitable at TC +3 or higher with Hi-Lo. A short list of strategy departures known as the Illustrious 18 covers the most valuable plays: stand on 16 vs 10 at TC 0 or higher, stand on 12 vs 3 at +2, and so on (index numbers quoted for a 6-deck H17 game).

Then there is money management. Risk of ruin drops sharply once your bankroll covers 100+ max bets, and serious counters play with 200–400 — see card counting bankroll for how to size units. And know the legal ground you stand on: counting with your brain is legal everywhere in the US, though casinos may ask you to leave. The full picture is in is card counting illegal.

The edge only shows up with volume, and volume is free here: the trainer's million-hand simulations show the ramp bettor pulling away from the flat bettor over the long run. Practice until the deck runs out at zero every single time.

Educational content only. Practice with fictional chips on our free trainer — no real money, no casino affiliation. 18+.

Frequently asked questions

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

In Hi-Lo, cards 2 through 6 count as +1, cards 7 through 9 count as 0, and tens, face cards, and aces count as -1. It is a balanced count, so a full 52-card deck sums to exactly zero. You keep one running total as cards appear, then divide by the decks remaining to get the true count.

How fast should I be able to count down a deck with Hi-Lo?

Fast enough to hold a perfect count at real dealing speed, with conversation and chip handling in the mix. Because Hi-Lo is balanced, a correct full-deck runout always ends on exactly zero, which makes the drill self-checking. Build accuracy first — a fast wrong count is worse than no count — and let speed come from repetition.

Is Hi-Lo better than KO or Hi-Opt II?

Hi-Lo offers the best balance of power and simplicity, which is why it is the most widely used counting system. KO is unbalanced and skips true-count conversion, making it simpler in play but coarser for bet sizing. Hi-Opt II is stronger but is a multi-level count that also requires an ace side count — a lot of extra work at the table for a modest gain.

How much of an edge does the Hi-Lo system give a card counter?

On a good 3:2 shoe game with a proper bet spread, a Hi-Lo counter earns roughly +0.5% to +1.5% over the house, compared with about -0.5% for basic strategy alone. Each true count point is worth roughly a +0.5% edge shift to the player. Avoid 6:5 tables entirely — the reduced blackjack payout adds about 1.4% to the house edge and makes counting effectively worthless.