Closing line value (CLV): what it is and how to measure it

The closing line and closing line value

The closing line is the last price before the event starts. By then the market has absorbed everything available: line-ups, injuries, weather and the money of well-informed bettors. That is why the closing price of a liquid market is considered the best available estimate of the true probability.

Closing line value (CLV) measures whether you bet at better or worse odds than that closing price. If you got 2.20 and the market closed at a fair 2.05, you took a price the market later judged too high.

The formula with an example

CLV % = your odds ÷ fair closing odds − 1

"Fair" means the margin has been removed. Otherwise you compare your odds with a price that contains the bookmaker's margin, and you systematically understate your CLV.

Had you bet at 1.95, CLV would be 1.95 ÷ 2.05 − 1 = −4.9%. How to remove the margin is shown in no-vig fair odds. If your bookmaker passes on Austria's 5% betting fee, use your odds after the deduction: 2.20 × 0.95 = 2.09 gives only +2.0%.

Why CLV tells you more, sooner, than profit

If the fair closing price is a good estimate of the probability, your CLV is an estimate of your expected value. The advantage: it scatters far less than results do.

• Results. At odds around 2.00 you win or lose roughly your whole stake on every bet. The uncertainty in your return only shrinks with the square root of the number of bets: about ±10 percentage points after 100 bets, still about ±3.2 after 1,000. A true return of 3% is barely distinguishable from zero after 1,000 bets.
• CLV. The CLV of a single bet varies by only a few percent. Assume ±4%: then the average after 100 bets is already accurate to about ±0.4 percentage points.

That is why professional bettors and bookmakers alike watch CLV. A consistently positive CLV against a liquid market is one of the strongest signals that someone is beating the prices. Bookmakers also use it to decide which accounts to limit.

The ± values are one standard deviation under simplified assumptions (independent bets, odds around 2.00). They show orders of magnitude, not a forecast.

Measuring CLV: source and timing

• Source. Use the closing price of a market with a low margin and high limits, meaning a sharp bookmaker or a betting exchange, or the margin-free average of many bookmakers. The closing price of your own soft bookmaker is a weak reference; sharp vs soft bookmakers explains why.
• Timing. As close to the start as possible, ideally the last price before kick-off. A price from two hours earlier often does not yet reflect the line-ups.
• Both sides. Record every price in the market, not just your side; otherwise you cannot remove the margin.
• Same market. The same line and the same rules. A −0.5 handicap cannot be compared with −0.25.

CLV in your records

A spreadsheet is enough. For each bet you need these columns:

What matters is the average across all bets, weighted by stake. A single bet with +7.3% CLV can lose, as in the example; that tells you nothing. Why individual results swing so much is covered in betting variance.

Limits of the method

• Thin markets. Lower leagues, women's football and specials attract little money. Their closing price is a weaker estimate, and a positive CLV proves less.
• No reference for local markets. Some matches and bet types are only offered by local bookmakers. Their closing prices often carry a high margin and barely move. According to our research, residents of Austria and Slovakia have no sharp bookmaker or exchange they can legally use; you can still read those prices as a reference.
• Systematic effects. For outsiders, the fair closing price depends noticeably on the devig method. Stick to one method so your numbers stay comparable.
• CLV is not profit. It is an estimate. You only get paid if the bet wins, and betting fees, limits and failed bets still come off.

CLV and sure bets

CLV does not affect the result of a sure bet: the margin is fixed once all legs are accepted at the shown odds and stand. It is still worth a look. Sure bets usually arise because one bookmaker lags behind the market, so its side often has a clearly positive CLV. That bookmaker sees exactly this in its own analysis, and people who place many high-CLV legs with it tend to be noticed sooner. For value bets, CLV is the key control figure; in ArbVantage value bets are coming soon. More on the background in value betting.

Frequently asked questions

What is a good CLV?

Any average that stays above 0% over time, measured against a fair closing price from a liquid market, is a good sign. Use the odds you actually get after any betting fee. Single bets say little; the average across many bets is what counts.

Do you need CLV for sure bets?

Not for the result of a sure bet: the margin is fixed once all legs are accepted at the shown odds and stand. Bookmakers do look at their customers' CLV, though. People who regularly take prices that later drop are more likely to be limited.

How many bets do you need before CLV means something?

For profit, often thousands, because at odds around 2.00 each result swings by about the whole stake. For the average CLV, a few hundred bets are usually enough, because it varies far less per bet. There is no fixed number.

Sources

• Štrumbelj (2014): On determining probability forecasts from betting odds, International Journal of Forecasting 30(4)
• Kaunitz, Zhong, Kreiner (2017): Beating the bookies with their own numbers, arXiv:1710.02824
• Clarke, Kovalchik, Ingram (2017): Adjusting Bookmaker's Odds to Allow for Overround, American Journal of Sports Science 5(6)
• Unternehmensserviceportal (USP, Austria): Wettgebührenabrechnung

As of October 2026. Fair closing odds in the example are rounded to two decimal places.

Betting involves risk, sure bets included: odds change, bets get voided and accounts get limited. Only bet money you can afford to lose. Our responsible gambling page lists free help.

Not betting, legal or tax advice. 18+. As of October 2026. See our disclaimer.