How to Use Market Width in +EV Sports Betting

What is Market Width in Sports Betting?

Market width is a term that is used to describe the difference between odds for a single game. It is important to consider when you are looking for bets that are mathematically profitable, or have positive expected value. Using an example from OddsJam’s Positive EV Betting Tool below we see the moneyline highlighted for the Arkansas vs Kansas State basketball game. This bet is a positive EV play – looking at the lines at Pinnacle, which is considered to be the sharpest sportsbook, we see some value on Kansas State +380. Using a no-vig odds calculator we see that the fair odds (odds after the vig has been removed) have Kansas State at +320. We can bet them at +380 at Barstool and BetRivers.

There is an additional consideration when looking at this bet – and that is market width. 

How to Calculate Market Width in Sports Betting

In the example above we see the Pinnacle moneyline odds of -398 Arkansas and +301 Kansas State. The market width here would be 97 cents difference between the two lines (398-301=97). This is an extremely wide market. So while Kansas State moneyline is a positive EV play, the market width should cause some concern. Market width can be used as an indicator of how confident books are in their lines. Pinnacle being the sharpest sportsbook, market width on their odds can be used to help evaluate different positive EV betting opportunities. The wider the market, the less confident the sportsbook is in their lines. Tighter lines indicate that a sportsbook is extremely confident in their lines.

How to Use Market Width to Evaluate +EV Bets

In a different example we see a much tighter market for the player prop bet Kyle Kuzma over/under 7.5 rebounds. The market width at Pinnacle for this bet is 31 cents, meaning that they are more confident in their lines. We also see this is a +EV bet with Pinnacle making the under at -114 and Caesars giving you +115. The fair odds for the under based on Pinnacle’s market are +101 so there is definitely some value there on a much tighter and more confident market than the above Arkansas/Kansas State example. It is worth noting that this is a player prop bet, which tend to have a lot more variance than a standard side or total – but it serves as a good example of a tight market. 

Ideal Market Width in Sports Betting

As a rule of thumb – the max market width that should be considered is between 20-25 cents.

Positive EV betting opportunities are a great way to evaluate sports bets, however it shouldn’t be considered blindly. You can use market width to help narrow down those opportunities to bets where the sportsbooks are much more confident in their lines. When looking at OddsJam’s Positive EV Betting Tool page – +EV plays between 2-6% will usually show bets that have the ideal market width.

Also check out how to read fractional odds, decimal odds, and how to calculate units!

As always, you can email sports betting questions to [email protected].