CLV calculator
Did you beat the close?
Last updated 2026-07-03
Closing line value is the sharpest measure of betting skill: it compares the price you took against the market's final, most informed price. Enter both in American odds.
How it works
Both prices convert to implied probability. CLV in probability points =
closing implied % - your implied %.
Positive means the market moved toward your bet after you placed it: you got a price the
close no longer offers. Across hundreds of bets, average CLV converges on your true edge
roughly ten times faster than realized profit does.
Purists devig both prices against the full market before comparing. This tool reports the raw implied-probability delta, which is the standard quick measure; for devigged fair probabilities use the no-vig calculator on both markets first.
Do this programmatically
Tracking CLV at scale needs the price at bet time and the price at close for every bet. Capture both from the live feed, or pull closes from the historical archive:
curl "https://api.theoddsapi.com/historical/odds?sport_key=basketball_nba&bookmakers=pinnacle" \ -H "x-api-key: YOUR_API_KEY"
Business tier. Query the snapshots nearest each game's start time for an effective close. The backtesting guide covers the full workflow.
Questions
Which closing line should I use?
Pinnacle's, when available. It is the most efficient close in the market. Using a soft book's close flatters your CLV because their lines lag.
Is positive CLV a guarantee of profit?
Over the long run it is the best predictor there is, but a bet can carry positive CLV and lose, and vig still has to be cleared. Consistent CLV above the vig is the target.
More tools: Odds converter · No-vig fair odds · Arbitrage · Parlay