Closing Line Value (CLV) Calculator

This calculator measures closing line value—how much better the American odds you bet were than the price that same market closed at—so you can track whether you’re consistently beating the sportsbook’s sharpest number over time.

What Is Closing Line Value?

Closing line value, or CLV, is the gap between the price you bet and the price that same market closed at. It is the single most respected proxy for a betting edge, because the closing line—the last price before kickoff—is the sharpest number the market produces, sharpened by every dollar and every piece of information right up to the whistle. Injury reports, weather updates, and sharp money all get folded into that final price, which is why serious bettors treat it as the market’s best estimate of the true probability.

If you consistently bet at better odds than the close, you are beating that estimate, and over a large sample that almost always means you are a long-run winner. This is what makes CLV valuable: it does not depend on whether any single bet actually won. A bettor can lose a game outright and still have gotten a great number, or win on a price the market later proved too generous. A single bet’s result is noise; your CLV over hundreds of bets is signal. That is why sharp bettors, and even sportsbooks themselves, watch CLV closely—books limit customers who consistently beat the close because it signals real skill rather than luck.

How Closing Line Value Is Calculated

To find CLV, first convert both the price you bet and the closing price to decimal odds. Then apply this formula: CLV % = (your decimal odds / the closing decimal odds − 1) × 100. A positive result means you got a better price than the close; a negative result means the market moved against you before kickoff.

Take a bet placed at +150, which converts to decimal odds of 2.50, on a market that closed at +120, which converts to decimal odds of 2.20. Dividing your decimal odds by the closing decimal odds gives 2.50 / 2.20, and subtracting 1 and multiplying by 100 turns that ratio into a percentage. The sign of the result tells you everything you need to know at a glance: positive means the market moved toward your side after you bet, confirming the price you took carried value; negative means the market moved away from you, and the number you got was worse than what the market eventually settled on.

For the cleanest read, don’t compare your bet against the raw closing price. Compare it against the no-vig closing line instead—the fair price with the sportsbook’s built-in margin stripped out. The raw close still contains that margin, so measuring against it makes your CLV look better than it really is. Stripping the vig first gives you a stricter, truer benchmark for how much value you actually captured.

What the Calculator Shows You

Once you enter the American odds you bet and the American odds the market closed at, the calculator returns your CLV as a percentage. That single number tells you, at a glance, whether the price you took was better or worse than the market’s final, sharpest estimate, and by how much. A positive percentage means you beat the close; a negative percentage means the close beat you.

The calculator is built to be read one bet at a time, but its real power comes from tracking that percentage across many bets. Logging your CLV on every wager, win or lose, builds a running average that reflects the quality of your bet selection and timing, not the outcome of any one game. Watching that average move gives a far more honest picture of whether you have a real, repeatable edge.

Worked Example

Say you bet an underdog at +150, and the market closed at +120. Converting each price to decimal odds gives you 2.50 for your bet and 2.20 for the close. To find your CLV, divide your decimal odds by the closing decimal odds: 2.50 / 2.20. Subtract 1 from that result and multiply by 100 to express it as a percentage. The answer is 13.6%.

That positive 13.6% is the whole story. You took 2.50 and the line closed at 2.20, so you beat the close by 13.6%. The market moved toward your side after you placed your bet—strong evidence the price you got carried value, whatever the game’s actual result turns out to be. If that underdog goes on to lose, the bet was still a good one by the market’s own later judgment; if it wins, the win is confirmation rather than the whole proof.

This is the core discipline CLV teaches: separate the quality of a bet from the outcome of a game. A bettor who takes +150 on that underdog and watches the number shorten to +120 by kickoff picked a price the market itself came to agree was too generous to the book—information, line movement, and betting volume all pushed the true probability closer to the bettor’s side after the fact. Do that over and over, across hundreds of bets on different games, and a positive average CLV becomes very hard to explain by luck alone. It is the clearest available signal that your process for finding and timing bets is sound, independent of how any single game happens to end.

CLV by the Price You Took vs the Close

The table below shows how CLV shifts across a range of bet-and-close pairs, from big favorable moves to a price that actually got worse. Notice that CLV can be strongly positive even when both prices are favorites, and that a small unfavorable shift, like taking -110 on a line that closes at +100, is enough to turn CLV negative.

The Bet and Closing Prices in Each Odds Format

Here is the same bet-versus-close comparison broken out into every format you’ll encounter: American, decimal, and implied probability. Your bet at +150 carries an implied probability of 40.0%, while the closing line at +120 implies 45.5%—a gap that shows the market judged your side more likely to win than the price you got suggested.

CLV as a Long-Run Signal, Not a Single-Bet Guarantee

CLV is a long-run diagnostic, not a promise about any one bet: you can beat the close and still lose the game, or take a bad price and win. Its value shows up only across a large sample, where consistent positive CLV lines up almost perfectly with profit. Treating a single reading as proof of anything misses the point of the metric—it is meant to be aggregated, not read in isolation.

Two refinements matter when building that track record. First, compare against the no-vig closing line, not the raw price. The raw close includes the book’s margin, so measuring against it flatters your CLV; the fair, no-vig number is stricter and truer. Second, use a sharp book’s close as the benchmark, since a soft book’s closing line is noisier and moves less efficiently, which can make readings bounce around without reflecting your actual bet selection.

Put those two refinements together and you get the strongest version of the signal: a steadily positive CLV against a sharp, vig-free close is the strongest evidence a bettor has a real edge. A negative average, no matter the current state of your bankroll, is a warning that recent wins were variance rather than skill.

When Closing Line Value Makes Sense

CLV is most useful as an ongoing habit rather than a one-time check. Every time you place a bet, logging the closing price for that market builds a track record that tells you something results alone cannot: whether your process for finding value is actually working. This matters most for bettors who bet frequently across many markets, since the signal only becomes reliable once it’s averaged over a large number of bets.

It makes the most sense for anyone trying to separate skill from luck in their results. If your win rate looks good but your CLV is flat or negative, be cautious about your bankroll growth—recent wins may be variance rather than a repeatable edge. If your CLV is consistently positive even during a losing stretch, that is reason for confidence that your process is sound and results will turn around given a large enough sample.

CLV makes less sense for judging any single wager, and it isn’t the right lens if you bet infrequently on only a handful of markets a year, since the sample will be too small to mean much. It also depends on a genuine closing price to compare against, so it works best on liquid markets rather than obscure lines that barely move. Used as intended—tracked consistently and benchmarked against a sharp-book close—CLV can tell a bettor whether they have a real edge before their bankroll has had time to prove it either way.

Common Mistakes

Judging a single bet by its result instead of its CLV over a large sample leads to false confidence or unnecessary panic. Measuring against the raw closing line instead of the no-vig one inflates your CLV and hides how much of that edge is really the book’s margin. Using a soft book’s noisy close as the benchmark produces readings that bounce around without reflecting your actual skill. Expecting positive CLV to guarantee a win on any individual bet misunderstands the metric—it predicts long-run profitability, not the outcome of the next game.

Closing Line Value vs Win Rate as an Edge Signal

Win rate feels intuitive, but it is driven by results and variance and needs a very large sample before it reliably predicts profit. CLV, measured against the market’s own closing price, predicts profit more strongly, needs a smaller sample to be meaningful, and isn’t fooled by short hot streaks.