Closing Line Value Calculator (CLV)
Did you beat the closing line? This closing line value calculator de-vigs the close, finds the fair probability for the side you took, and subtracts the probability your own price implied. The gap — your CLV, in probability points — is the fastest-converging measure of betting skill there is. Enter your numbers below and get a graded result, every step shown.
Want every bet graded automatically, with the CLV lesson on each one? Open the tool in the app →
How the closing line value calculation works
CLV asks a single question: was the price you locked in better than the market’s final answer? The closing line is the sharpest number the market produces — it arrives after all the money and information have. If you consistently got a better number than the close, you were picking good prices, and that shows up long before your win rate does. The whole calculation is three short steps.
First, convert the price you got into the probability it implies:
Second, de-vig the closing line to get the fair closing probability of the side you bet — the two closing prices carry the book’s margin, so you strip it out (proportional shown; power and Shin are options above):
Third, closing line value is simply the fair closing probability minus your price’s implied probability, in percentage points:
Positive CLV means the fair close was higher than the price you paid for — you beat the closing line. Negative means the market moved against you and you were on the wrong number.
The A–F grade scale
Raw probability points are hard to feel, so the calculator grades them. Small edges matter here: beating the close by even a point or two, held consistently, is the signature of a sharp bettor.
- A — +2.5 points or more. You clearly beat the closing line.
- B — roughly +1.0 to +2.5 points. Solidly on the right side of the close.
- C — a narrow band around zero. You essentially matched the market’s final number.
- D — down to about −2.0 points. The close moved against your price.
- F — below −2.0 points. You were well on the wrong side of the closing line.
Worked example
You took side B at +130. The market closed side A −140, side B +120. First, your price’s implied probability:
Now de-vig the close. Both closing prices in implied-probability terms:
They sum to 103.8% — that excess is the vig. Rescale to get the fair closing probability for your side, B:
Closing line value is the difference:
Every CLV grade rests on a clean de-vig, so it’s worth learning that step on its own with the no-vig calculator. Once you can grade your prices, size them with the Kelly calculator and check individual bets with the expected value calculator. The full method, with the de-vigged closing consensus behind it, is in closing line value explained.
Frequently asked questions
What is a closing line value calculator?
A closing line value calculator compares the price you got to the de-vigged fair probability of the closing line. It removes the vig from the close, finds the fair probability for your side, subtracts your price’s implied probability, and reports the difference in probability points — your CLV. Positive means you beat the closing line.
Why is closing line value the best measure of betting skill?
The closing line is the market’s sharpest estimate, set after all money and information have arrived. Consistently beating it means you got a better price than the final consensus. CLV converges on your true edge far faster than win rate, which is buried in variance for hundreds of bets — so a few dozen graded bets already tell you whether you are picking good numbers.
What counts as a good CLV, and what earns an A?
On this scale an A is +2.5 points or more of closing line value, B is roughly +1 to +2.5, C is a narrow band around zero where you essentially matched the close, D runs down to about −2 points, and anything below −2 points is an F. A small but steadily positive average CLV across many bets is the signature of real skill.