What Is Closing Line Value (CLV) in Sports Betting?

Closing line value (CLV) is the difference between the odds you bet and the odds the market settled on when the event started. If you took a better number than the closing line, you have positive CLV, and over a large sample that is one of the most widely used signs that you are getting good prices. It does not promise that any single bet wins. This guide explains what closing line value means, how to calculate it, why sharp bettors track it, and how to measure your own.

Closing Line Value Calculator

Drop in the price you took and both sides of the closing line. The calculator removes the vig from the close, finds the fair probability, and scores your price as an expected value percentage, the same way the SmartStake bet tracker does.

Beating the close by a few percent, like the example above, is a strong result. To understand why, start with what the number actually means.

What Closing Line Value Means

Closing line value is how much better, or worse, your odds were than the market's final line. Bet a team at +120 and watch it close at +100, and you beat the close: you locked in a bigger payout than the market's settled price. Take +100 on a team that drifts out to +120 by kickoff, and you got the worse number.

The closing line is the last price a book posts before an event begins, after every sharp bettor, syndicate, and late injury report has moved the market. It is among the most scrutinized and efficient numbers a book posts all day, which makes it a strong estimate of an outcome's true probability. Your price beating that estimate is evidence you found value before the rest of the market did.

That is the whole idea. Now for the math that turns "I beat the close" into a number you can track.

Calculating Your CLV

Scoring your CLV takes three steps: convert the odds, remove the vig from the close, then compare.

1. Convert to decimal. Decimal odds make the math clean, and 1 divided by the decimal price is the implied probability. Our odds converter handles American to decimal if you need it.
2. De-vig the close. The closing line still carries the book's margin, so you strip it out to find the fair probability. Removing the vig is its own skill, covered in the de-vig playbook.
3. Compare your price to fair. Your CLV is the expected value of the price you took, measured at the fair closing probability.

Here is a worked example that matches the calculator above. You bet the Lakers at +120, which is 2.20 in decimal. At tip-off the market closes with the Lakers at +100 (2.00) and the other side at −120 (1.833).

Convert the close to implied probabilities: the Lakers imply 50%, the other side implies 54.5%, a total of 104.5%. That extra 4.5% is the vig. Remove it and the Lakers' fair probability lands near 47.7%, a fair closing price of roughly +110. Your +120 is a longer price than that fair +110, so you beat the close.

Put it in one line:

$$CLV = o_{taken} \times p_{close} - 1$$

where o is the decimal price you took and p is the fair closing probability. With o = 2.20 and p = 0.477, your CLV is 2.20 times 0.477 minus 1, or about +4.9%. You beat the close by roughly 5%.

If that formula looks familiar, it should. It is the expected value formula from the positive EV guide, anchored at the closing probability instead of a live sharp line. CLV is simply EV measured against the close. You do not have to run it by hand: the de-vig calculator turns two closing prices into fair odds in a click.

Why CLV Predicts Long-Term Results

Here is why bettors obsess over this number. The closing line is about as efficient as a betting market gets, so consistently beating it means you are consistently finding value the market later confirms.

The research supports the idea. Studies of closing odds have found a close correlation between the value a price implied and the profit bettors actually realized in those datasets, which is the same evidence behind why SmartStake trusts sharp closing lines as a benchmark for true probability. Past results in research samples do not guarantee your results.

CLV is a read on the quality of your prices, not a promise about outcomes. A bet can beat the close and still lose, and a poor price can still win. That is what makes CLV useful. Your win-loss record needs hundreds of bets before variance settles enough to mean anything, and a good process can look like a bad one for a long time in between. CLV surfaces the quality of your process much faster, because it grades the price, not the result.

Price CLV vs No-Vig CLV

People measure CLV two ways, and the difference matters.

Price CLV compares your odds to the raw closing odds and ignores the vig. It is simple, but the closing line still has the book's margin baked in, so the number flatters you.

No-vig CLV first removes the vig from the close, then compares your price to the resulting fair odds. It is stricter and more honest, because it asks whether you beat the market's true estimate rather than its marked-up one.

SmartStake uses no-vig CLV by default. The calculator above and the bet tracker both de-vig the close before scoring your price, which is why the fair closing odds they show are a little shorter than the raw line you would see on the board.

Tracking CLV Automatically

Scoring one bet is easy. Scoring every bet, capturing each closing line the moment its event starts, is not. That is the job the SmartStake bet tracker does for you.

It captures the closing line for your bets, de-vigs it against the sharp books that move the market like Pinnacle, Circa, and FanDuel, and reports your CLV automatically. You see your average CLV as an expected value percentage, the share of your bets that beat the close, and how many came in positive, negative, or even, across any window from today to all time.

CLV tracking launched in beta recently. You can read what it does in the product update and see the wider reporting in the performance dashboard guide.

Good CLV usually starts with good bet selection. The positive EV tool surfaces prices that beat the sharp line right now, which is the same edge that shows up as positive CLV once the market closes.

Track your closing line value free.

Frequently Asked Questions

The Bottom Line

Closing line value tells you whether you are getting good prices long before your record can. Beat the de-vigged close consistently and you are consistently finding value, though results vary and no single bet is guaranteed. Learn to spot value in the positive EV guide, sharpen your fair-odds math with the de-vig calculator, and let the bet tracker score your CLV on every bet automatically.