Quick answer
Closing line value: Closing line value measures how the price you took compares with the final price before the event starts; consistently getting better prices than the close is a widely used sign of skill.
Also called: beating the close
Explained, with an example
The closing line is the last price before kickoff, after the market has absorbed the available information, so it is treated as the best public estimate of the true probability [1]. A simple measure is odds taken / fair closing odds − 1: taking 2.10 when the no-vig close is 2.00 gives +5% CLV. Odds-API.io's CLV tutorial notes that you must log both your price and the fair price at that moment, because neither can be recovered later [1].
Formula
CLV = odds taken / fair closing odds − 1Try it: tools and tutorials
Frequently asked questions
What is closing line value?
Closing line value measures how the price you took compares with the final price before the event starts; consistently getting better prices than the close is a widely used sign of skill.
About this guide
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Author: Ken Lin · Corrections: if you spot an error, we review it and date-stamp the fix.
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Sources
- Value Bets API: Track Closing Line Value in Python — Odds-API.io blog, accessed 2 Nov 2026