Glossary

What is closing line value (CLV) in sports betting?

Last updated 2026-07-04

Closing line value is the difference, in implied probability, between the price you bet and the market's final price before the game starts. Consistently beating the close is the strongest available evidence of real betting skill, because the closing line is the market's most informed number.

The logic: by the time a game starts, every piece of public and sharp information has been bet into the line. If you took +150 on Tuesday and the same outcome closes +120, the market moved toward your position, and you hold a price it no longer offers. Do that consistently and you have edge; whether any single bet wins is noise.

The math: convert both prices to implied probability and subtract. +150 implies 40.0%, +120 implies 45.5%, so the CLV is +5.5 probability points. Purists remove the vig from both markets first (see no-vig fair odds); the raw delta is the standard quick measure.

CLV converges on your true edge roughly ten times faster than profit does. A few hundred bets of positive CLV means something; a few hundred bets of profit can easily be luck. Track it with the CLV calculator.

Compute it with the API

curl "https://api.theoddsapi.com/historical/odds?sport_key=basketball_nba&bookmakers=pinnacle" \
  -H "x-api-key: YOUR_API_KEY"

Capture the price at bet time from /odds/, then pull the snapshots nearest each game's start from the historical archive for an effective close. Pinnacle's close is the benchmark. Free key in minutes.