Ballwise · free tool
How did your price hold up at the close?
Free closing-price check. Enter the price you took and both sides of the closing market. You get the fair closing chance with the book's margin taken out, and how far your price was from it.
Your price vs. the close
American odds. The line number is optional (for example 5.5); fill it in when the line itself could have moved.
How it is calculated
Every American price converts to an implied chance: a negative price -A gives A / (A + 100), a positive price +B gives 100 / (B + 100). The two closing prices add up to more than one whole; the extra is the book's margin. Dividing each side by the total removes it (multiplicative devig, the same math as the price check). Closing line value (CLV) is the fair closing chance minus the chance your own price implied, in percentage points. Expected value per $100 is what that bet returns on average if the fair closing chance is the true chance: fair chance times your decimal payout, minus one, times 100.
If the line number changed between your bet and the close (say you took over 5.5 and it closed at 6.5), the two prices are for different bets and can't be compared directly. The move itself is the signal: a line that moved toward your side means the market came around to your number.
Why CLV matters more than wins and losses
A single bet wins or loses mostly on luck, and it takes hundreds of results before a record says much about skill. The closing price is the market's last and best-informed estimate, so it is available the moment the game starts. If you keep getting prices better than the fair close, you are paying less than the market's final view of the chance; if you keep getting worse ones, you are paying more. It is a measure of the price you paid, not a promise about any result.
Math tool for entertainment & information. Not a sportsbook. 21+. 1-800-GAMBLER. Results are arithmetic on the numbers you enter, not predictions.