Closing Line Value (CLV) Calculator
Enter the odds you took and the closing odds to get your CLV. Add the opposing side's closing odds and the tool de-vigs the close for a fair reading.
Fill in the fields above to see the result.
The calculator above answers one question: was the price you took better than the price the market closed at? That difference is your Closing Line Value, and it is the fastest signal that your read is right, long before profit tells you anything.
How the math works
With decimal odds, CLV comes out of one division:
CLV % = (your odds ÷ closing odds) − 1
Took 2.10 on a market that closed at 2.00? 2.10 ÷ 2.00 − 1 = +5%. You bought 5% cheaper than the market's final verdict.
Fill in the opposing closing price as well and the calculator takes one more step, stripping the bookmaker's margin before it compares. It turns both closing prices into implied probability (1 ÷ odds), adds them up, and divides each by the total:
fair prob = (1 ÷ your closing odds) ÷ (1 ÷ closing A + 1 ÷ closing B)
The fair odds are the inverse of that. Honest CLV is measured against them, because the raw closing price still carries the vig, and the vig makes everyone look better than they are.
Worked example
A game that closed at 2.00 on one side and 1.90 on the other. The implied probabilities add up to 102.63%, so 2.63% of margin is baked in. The fair price on the 2.00 side becomes 2.05.
| Your odds | Raw close | Raw CLV | Fair close | Fair CLV |
|---|---|---|---|---|
| 2.10 | 2.00 | +5.0% | 2.05 | +2.3% |
| 2.25 | 2.00 | +12.5% | 2.05 | +9.6% |
| 1.95 | 2.00 | −2.5% | 2.05 | −5.0% |
Look at the first row. Against the raw price you appear to have beaten the market by 5%. Against the fair price it was 2.3%. More than half of what looked like an edge was just the bookmaker's margin. Across a thousand bets, that gap is the difference between believing you have an edge and having one.
Where it misleads
A quiet market has no reliable close. If the line barely moved because almost nobody bet into it, the final price is not a verdict on anything. High CLV in a thin market is usually noise.
A postponed game ruins the reading. If the fixture was rescheduled, the odds you are calling the close may be from hours before the real kickoff. Always compare against the price immediately before the actual start.
CLV is not profit. It is a leading indicator, not a statement. A whole season of positive CLV can end in the red and still be good information. What it tells you is that you are buying cheap, repeatedly.
FAQ
Does positive CLV guarantee I will profit?
No. Nothing in betting guarantees profit. Positive CLV says you bought at a price the market later treated as too generous, which historically travels alongside positive results over a large sample. Over a small one, variance rules.
What counts as good CLV?
It depends on the market. In liquid markets, a sustained average between +1% and +3% against the fair line is already strong. Be suspicious of averages well above that: it usually means you are measuring against the raw price, or picking markets that are too thin.
Do I always need to remove the vig?
To compare yourself against yourself over time, no: the error is constant and cancels out. To know whether you actually have an edge, yes. The no-vig calculator does that step on its own if you want to see the numbers separately.
To follow this bet by bet without a spreadsheet, the bet tracking guide walks through the workflow, and the CLV guide covers the why. Betting is entertainment for adults 18 and over and carries a risk of loss.