Billy Walters Shares the Secrets Behind His Betting System

Widely considered the most successful American sports bettor ever, Walters shares his betting system in his new book "Gambler: Secrets from a Life at Risk" with Armen Keteyian. He spends two chapters discussing his system — here are some key learnings.

Aug 30, 2023 • 07:35 ET • 4 min read
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Billy Walters is widely considered the most successful American sports bettor of all time. The original Kentucky sports betting gambler has made hundreds of millions of dollars by beating sportsbooks over the past few decades — and has now decided to share his betting system with the world.

In Walters’ new book "Gambler: Secrets from a Life at Risk" with Armen Keteyian, he dedicates two chapters to his betting system, which he titles Master Class and Advanced Master Class. Here are some key learnings from both chapters that should help most bettors improve. 

Master Class

Master Class is aimed more at beginners, but there are still many takeaways that bettors need to be reminding themselves of at all times. Walters lists three main areas where bettors need to be astute in order to be successful: Handicapping, betting strategy, and money management. 


Walters' handicapping system revolves around power ratings (more on that below) but before getting into the details, he outlines the basics that everyone must understand:

  • Home field advantage. This is generally assumed to be worth three points. But from 1974-2022, it's actually only worth closer to 2.5 points. And over the last four years, it's worth less than one point.

  • Prevent. Which teams and coaches let up or sit starters with a big lead? Understanding these tendencies is crucial.

  • Injuries. Knowing which players will or won't play is obviously crucial, but understanding how much each player is worth to the line is just as important (more on this below). 

  • Game factors. There are also a ton of game factors that Walters evaluates each week. Divisional play, teams coming off of Thursday Night Football, consecutive weeks on the road, weather, and teams changing time zones are just a few of these factors.

Betting strategy

The single most important factor outlined by Walters when it comes to building a successful betting strategy is to get the best odds on every bet you make. How do you do that? By having as many accounts as you can with different sportsbooks or betting sites

Here are a few other things to keep in mind:

  • Monitor the odds at market-leading sportsbooks (Walters specifically names Circa, MGM, Caesars, and Pinnacle). The lines at these sportsbooks show you which way the odds are moving.
  • As a rule of thumb, bet favorites early and dogs late. 

  • Some key numbers in betting matter more than others, and you need to understand the value of half points

  • Don't chase losses by betting on games where you don't have an edge. 

Money management

Knowing how to manage your bankroll is almost as important as knowing how to handicap games and developing your betting strategy. First, you need to set your bankroll by deciding how much you want to risk. Walters says to "start with the assumption that you'll lose it all." Also, remember that you cannot bet without a bankroll. Protecting it should be your top priority.

Once you have your bankroll, you'll want to limit your maximum wager on any single event to three percent of your total bankroll. Walters also recommends betting in half units between 0.5 and three units. The more value you have in a bet, the more units you put toward it (with the maximum being three units).  

Advanced Master Class

Now, let’s take a deeper look at how Walters handicaps sports, specifically power ratings. He uses the NFL as his example, but many of the strategies can also be applied to other sports.

Power ratings are key to Walters’ approach to handicapping as they ultimately help him arrive at a predicted game score. Once he has a predicted game score, he compares it with the posted point spread from sportsbooks and then acts accordingly.  

Obviously, keeping accurate power ratings that are better than those of the oddsmakers at sportsbooks is no easy task. Walters has a large team of bright individuals behind his power rankings, and his approach to creating and updating them is complex. Here are a few factors that go into his power ratings.

Relative power of teams

Essentially, this is the raw power rating of each team on a neutral field. Walters’ team starts with a strong initial power rating and then calculates new ratings weekly for every NFL team. The ratings are numerical and help him arrive at an expected point spread by calculating the difference between the two teams’ ratings. But this is just the beginning, as now he’ll adjust the numbers by adding in a number of game-specific variables.

Player rankings

Having accurate player rankings is important as it helps numerically account for injuries. Walter says that properly assessing injuries is the “second-most important factor in gaining a handicapping advantage in sports.” He assigns numerical values for all key players in the NFL (though admitting that at least 60% of players have a value of basically zero) — here are some important factors to keep in mind:

  • QBs are worth about a touchdown. The best ones are worth more.

  • The top non-quarterbacks are worth between 2.5-3 points.

  • Because QBs are so valuable, Walters keeps a quarterbacks-only rating system in addition to his non-QB player rankings.

  • Player values must be adjusted if that player is playing hurt.

  • Stack/cluster injuries matter, especially to pass catchers, defensive line, offensive line, defensive backs, linebackers, and running backs (in that order).

  • Monitor beat writers and pro football medical experts (such as @profootballdoc and @FBInjuryDoc) on social media to help predict whether a player will suit up or not.

Game factors

Walters lists a number of game factors that must be considered when adjusting power ratings to arrive at a predicted score:

  • Home field advantage

  • Expected weather

  • Each team’s previous schedule (byes, multiple away games, etc.)

  • Travel distance/difficulty

  • Stadium quirks

  • Turf types

Walters even goes as far as to classify these into S-factors (special situations), W-factors (weather), and E-factors (emotional). He has dozens of factors listed and quantified based on long-term statistical analysis that is then updated year to year. Here are a few examples:

  • Turf: Walters upgrades the visitor if the home and visitor have the same turf. If they have opposite turf, he upgrades the home team.

  • Bounceback: Walters upgrades a team who lost its previous game by 19+ points (and upgrades them slightly more if they lost that game by 29+ points).

  • Super Bowl: The winner of the Super Bowl gets upgraded for its first four games of the next season; the loser gets downgraded for its first four.

  • Schedule: Walters says one of the biggest downgrades in terms of scheduling quirks is when a team is on the road and coming off a Monday Night Football game.

Creating/updating power ratings

As mentioned earlier, power ratings must be maintained and updated each week of the season. A team’s new power rating is calculated by using 90% of its old rating plus 10% of what he calls the True Game Performance Level, a somewhat complicated formula that is well described in the book.

But the most important thing to remember (and reiterate) here is that only 10% of the new rating is derived from the previous week’s result. This ensures that he updates his ratings weekly while not overreacting to the previous week’s game.

The above looks at just a few of the advanced handicapping strategies outlined by Walters in Gambler: Secrets from a Life at Risk with Armen Keteyian. The book was released on August 22, 2023 and is widely available for purchase across the U.S. and Canada.

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