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Can you win at Blackjack?

Can you win at Blackjack?

Yes, if you put in the work

George Pillari
September 04, 2025

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Ed Thorp wanted to count to a million. Back in the day when hard-copy catalogs were in mailboxes, the Sears catalog reigned supreme at over 1,000 pages. Thorp figured he would count items in the catalog to get a million.

He fell asleep somewhere in the 30,000s. When he woke up, he picked up exactly where he had left off. Ed Thorp was eight years old.

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Thorp grew up as a mathematical genius. He was a professor in the 1960s and 1970s and published Beat the Dealer, which was a detailed guide on how to count cards and beat the house in the game of blackjack.

In blackjack, each player at the table (usually five or six players) is dealt two cards, both are face up while the dealer’s hand has one card face up and the other face down. The goal is to score 21 or as close to 21 as you can without going over. Scoring 21 in two cards, an ace plus a 10 or a picture card, is the name of the game and it usually pays 3:2 or 2:1 on your bet.

Professor Ed Thorp

But while scoring 21 in two cards might happen once or twice if you play for a few hours; it's the strategies used on everything in between those perfect hands that matter. There is a generally accepted strategy for when to “hit” and when to “stand” that has been reduced to a simple grid.

The basis of blackjack strategy is not going for 19, 20, or 21 by hitting and taking more cards. The guts of the strategy are to stand and let the dealer take the hits and bust by going over 21.

Let’s do a few examples. Your two cards add up to seven. It does not matter what the dealer is showing; you will take a hit since you cannot go higher than 17 total (or 18 if you draw an Ace).

What about when your cards add up to 15 and the dealer is showing a five? The strategy assumes the dealer has a 10 or picture card face down. Using this assumption, you stand on 15 and let the dealer take a hit and likely bust by going over 21. Not exciting, but effective.

The strategy gets more interesting when the odds are in your favor. Say your two cards add to 11 and the dealer is showing a five. You know you should hit since you cannot go over 21, but in this case you “double-down” or double your bet and then you can only take one card, hoping it will be a 10 or picture card giving you 21.

You can learn basic strategy in a few hours of playing with a deck of cards or using a blackjack training site. Playing basic strategy reduces the house’s advantage to less than one percent. If you go on a winning streak, pick up your chips and stop before the odds swing back in favor of the house, which they always will over the course of a large number of hands.

To move the odds in your favor, you need to count cards. Counting cards, like the basic strategy grid, is simple to learn. Counting cards is a method of keeping track of what is left in the decks of remaining cards.

In order to count cards, you have to carefully look at each card that is on the table and develop a running count, meaning your counter starts at zero and then changes with each care that is dealt. (Our discussion uses a simplified version of the running count.)

For every card that is a six or less, add one to the running count. For sevens, eights, and nines, add zero to the running count. For 10s and up, subtract one from the running count. You must count all cards on the table from all hands, not just yours.

How to do a running count

When the running count is positive, this is a signal to increase your average bet.

A high running count indicates there are more 10s, picture cards, and aces remaining in the deck and this is good for the player for two reasons: (i) higher chance of scoring 21 in two cards and (ii) greater chance of the dealer hitting, getting a high card, and busting.

Never forget you will win more hands watching the dealer bust than you will with a high score in your hand.

The combination of basic strategy plus card counting swings the one percent house advantage to a one to two percent advantage for the player. It’s a big deal, and that is why card counting is illegal — if you get caught.

What Thorp taught us makes intuitive sense; minimize your losses until the odds are in your favor, then go big.

For Ed Thorp, it was all an academic exercise to prove mathematical theories. He did not set out to force Las Vegas to change the rules, but that is exactly what happened.

Because of Thorp, dealers now use five or six decks, which makes counting more difficult and all casinos now have a policy that permits them to refuse service to any player. The blanket refusal approach avoids haggling with customers over whether they are counting cards. And all those surveillance cameras? They allow agents in the control room to scan the crowd for suspected card counters.

Thorp later took his minimize-the-losses strategy to Wall Street, pioneered the field of algorithmic trading, and ran one of the most successful hedge funds ever.

Key Takeaways

Risk management is a fancy term for being careful. In betting and investing, any professional will tell you it is more about minimizing losses than scoring outsized gains.
Blackjack strategy provides a good life lesson: wait until the time is right before moving aggressively.
You can learn blackjack strategy pretty easily. There is no excuse to play the game emotionally and impulsively. It may be less fun, but it will be more profitable.

Things I think about

Going to the moon takes about three days. To Mars, about nine months. And to Jupiter, it would require five years.