Card Counting for Beginners: The Hi-Lo System

Card counting tells you when the cards left in the shoe favor you instead of the casino, so you can bet more at those times. Counters don't memorize every card. They keep one number in their head and update it as each card appears.

Learn basic strategy first. Counters still play basic strategy on the great majority of hands. Counting on top of a shaky strategy only loses money faster.

Why the remaining cards matter

When lots of tens and aces are left in the shoe, the game tilts toward you. When it's full of small cards, it tilts toward the dealer. High cards help you because:

• Blackjacks come more often. You and the dealer both get more of them, but only yours pay 3:2.
• Doubles work better. When you double on 9, 10, or 11, you're usually hoping for a ten.
• The dealer busts more. The dealer must hit 12 through 16, and a ten busts those hands. You get to choose whether to stand.
• Surrenders, splits, and insurance all become more valuable.

Small cards do the opposite. They let the dealer turn 12 through 16 into made hands without busting.

Here's roughly where a counter's extra value comes from:

Average conditions in a six-deck shoe.

The Hi-Lo count

Hi-Lo gives every card a value of +1, 0, or −1:

Each deck has as many +1 cards (2 through 6) as −1 cards (10s, face cards, and aces). If you count through an entire deck, you end back at 0. That makes Hi-Lo a balanced count.

The running count

Start at 0 after the shuffle. Add the value of every card you see. That total is the running count.

1. 5♠5+1= +1
2. K♥K−1= 0
3. 2♦2+1= +1
4. 9♣90= +1
5. A♠A−1= 0
6. 4♥4+1= +1
7. 6♣6+1= +2
8. 3♦3+1= +3

A positive running count means more small cards than big cards have been dealt, so the cards still in the shoe are rich in tens and aces. A negative count means the opposite.

A few habits make counting faster:

• Count every card you can see: your cards, other players' cards, and the dealer's hole card once it's turned over.
• Cancel pairs. A 5 and a king together are worth 0, so you can skip past them.
• Practice until it's automatic. The Card Counting Trainer deals cards at the speed you choose and checks your count.

The true count

A running count of +6 means a lot more with one deck left than with six. The true count adjusts for how many cards are left:

True count = running count ÷ decks left in the shoe

Here's the same running count at different points in a six-deck shoe:

You don't need exact division. Estimate how many decks are left, divide, and round. A rough estimate is good enough, and in most hands the right play is obvious anyway.

Some counting systems divide by half decks instead. In this lesson, Hi-Lo uses full decks.

Betting with the count

The higher the true count, the more you bet. A principle called the Kelly criterion says your bet should grow in proportion to your advantage. When the count is low or negative, you bet your minimum.

The ratio between your smallest and largest bet is your bet spread. With a 1 to 10 spread, your biggest bet is 10 times your smallest. A wider spread wins more over time, but it makes your bankroll swing harder and makes you easier to spot.

This simulation shows how spread and penetration (how much of the shoe is dealt before the shuffle) change a Hi-Lo counter's advantage:

Player advantage with Hi-Lo. Six decks, dealer stands on soft 17, surrender, double after split, resplit to four hands including aces, Illustrious 18 and Fab 4 plays. Bets raised only after a win and lowered only after a loss.

• A wider spread earns more.
• Deeper penetration earns more. The more of the shoe the dealer deals, the more often the count climbs high enough to matter.

In a six-deck game, 1 to 15 is about as aggressive as a spread should get. Raising your bet to more than double your last one is a quick way to draw attention.

Expect big swings

Even for a skilled counter, a realistic edge is only about 0.5% to 1.5%. The count is high enough to raise your bet only part of the time: roughly 10% to 35% of hands, depending on the rules, penetration, and strategy. In the short run your bankroll will rise and fall sharply, and it can take hundreds of hours of play for the edge to show. One popular rule of thumb is to keep a bankroll of 100 times your largest bet.

When insurance is worth it

The odds lesson showed why insurance is a bad bet for most players. It pays 2 to 1, so it only breaks even when more than one-third of the unseen cards are tens. Counters know when that's true:

Six decks. The insurance index is for the Hi-Lo true count.

Take insurance when the true count is +3 or higher, and skip it otherwise. Among the count-based changes to basic strategy, this one is worth the most. Lesson 6 covers the others.

Is card counting legal?

In the United States and the UK, counting cards in your head is not against the law. Using a device, or another person, to help you count is not allowed. But casinos are private businesses that don't like counters. Depending on where you play, a casino may:

• Ban you from blackjack or from the casino
• Shuffle early, or shuffle whenever you raise your bet
• Make you flat bet, or keep you from joining a shoe until the next shuffle
• Deal less of the shoe before shuffling

In New Jersey, Atlantic City casinos can't ban counters, so they rely on these other countermeasures instead.

Continuous shuffling machines and most online blackjack games shuffle so often that counting doesn't help.

Key takeaways

• Hi-Lo: +1 for 2 through 6, 0 for 7 through 9, −1 for 10s, face cards, and aces.
• The running count starts at 0 and adds each card's value.
• The true count is the running count divided by the decks left. Bet more when it's high.
• A wider bet spread and deeper penetration increase your edge, but big bet jumps attract attention.
• Take insurance at a true count of +3 or higher.
• Even done well, counting gives a small edge with big swings. It's legal, but casinos can ask you to leave.