Free odds calculator
Closing Line Value Calculator for Bets and AI Signals
By DeepChamp research team · Updated · Methods and limitations
Short answer
Closing line value compares the price you took with the market price at the close. Enter your entry odds and the closing odds of both sides, and the calculator shows the gap in probability points, with the margin removed, and the expected value of your price if the closing probability is right.
Closing line value calculator
American odds when the bet or signal was issued.
American odds at the start time.
Lets the calculator remove the margin.
| Break-even probability of the price you took | 51.22%at -105 |
|---|---|
| Closing probability, same side | 54.55%margin included |
| Closing probability, margin removed | 52.17%the fair comparison |
| Closing line value | +0.95 pointsagainst the margin-free close |
| Expected value per unit at the close | +1.86%if the closing probability is the truth |
Closing line value measures the quality of a price, not whether a bet won. Judge a source by the average over a large sample, not by one result.
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Download on the App StoreHow to use it
- 1Enter the American odds you took, or the odds that were available when a signal or pick was issued.
- 2Enter the closing odds for the same side and, if you have it, the closing odds for the other side so the margin can be removed.
- 3Read the gap in probability points. Positive means the market closed on your side of the price you took; negative means it moved against it.
- 4Repeat for every signal in a sample and average the gaps. One result says almost nothing; a few hundred say something about the quality of your prices.
How the math works
Closing line value measures price quality, not results. A bet can have positive closing line value and lose, and a bet can win after the market closed against it. Over a large sample, the closing price is widely used as the best available estimate of the true probability, which is why it is a common yardstick for judging a pick source or an AI agent without waiting for results.
Remove the margin before comparing. A closing price of -120 on both sides of a market does not mean 54.5 percent for either side; once the margin is taken out each side is 50 percent. The calculator removes the margin proportionally when you enter both closing prices and says so in the result.
- Break-even probability of the price you took
- p_entry = 1 / decimal_entry
- Closing probability with the margin removed
- p_close = (1 / d_side) / ((1 / d_side) + (1 / d_other))
- Closing line value in probability points
- CLV = p_close - p_entry
- Expected value at the close, per unit staked
- EV = decimal_entry x p_close - 1
Common questions
How do you calculate closing line value?
Convert the price you took to a break-even probability, convert the closing prices of both sides to probabilities and remove the margin, then subtract: closing probability minus entry probability. Positive means you took a better price than the market closed at.
Does positive closing line value mean a bet will win?
No. Closing line value measures the quality of the price, not the outcome of one bet. It is used over many bets as a check on whether a source of picks, or an AI agent, consistently finds prices that the market later agrees with.
Why remove the margin from the closing price?
Both closing prices contain the operator margin, so comparing your entry price with a raw closing price overstates or understates the gap. Removing the margin gives a probability that sums to 100 percent across the market, which is the fair comparison.
How can an AI agent measure closing line value?
Log each signal with its identifier, issue time and the entry price from your own licensed odds feed, read the closing prices from the same feed at the start time, and run this calculation for every signal. DeepChamp for Agents publishes a closing reference time on its signals, never a price, so your agent reads its own close.
This is educational research content. Examples use hypothetical numbers and are not live odds, picks, or claims about performance.
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