How to calculate Closing Line Value (CLV) in sports betting

• What is Closing Line Value and why it's important for sports bettors

• How to calculate CLV

• How to improve your CLV

Closing Line Value, or CLV, is one of those controversial topics among sports bettors. You'll have sharp bettors like Spanky preach the living crap out of CLV on Twitter and on his podcast Be Better Bettors. Still, you have plenty of well-known bettors (some good, some not so much) who deny it's a useful number at all.

From a statistics point of view, I agree with Spanky that CLV is crucial for bettors looking to step their game up. In this article, you'll have a better understanding of what it is, how to calculate CLV, and how to improve it.

By the end of this, hopefully you'll agree CLV is useful for you as a bettor and you'll know how to calculate it!

What is CLV?

Before we discuss what closing line value is, let's start with what the closing line is. Between the time the sportsbooks like DraftKings or BetMGM release the odds, and the time the game begins, the odds can change. This occurs when new information is discovered such as player injuries or weather. It can also change when the public or sharp bettors favor one side of the line or the other.

The Cincinnati Bengals opening line could be +4.5 on Monday, but a key player injury, inclement weather, sharp money, or any other factor could change that line to a +2 closing line by the time the game starts the next Sunday.

In short, the closing line value is the difference between the line you placed your bet at, and the closing line, measured in a percentage.

Let's take the above example. If you had favored Cincinnati to beat the spread and you bet at the opening line of +4.5, and the closing line was +2, you would have positive CLV. Nice job!

Why? Because betting that the underdog (Cincinnati in this case) will lose by less than 4.5 points is a much easier feat than them having to only lose by less than 2 points.

The rule of thumb is - If the closing line is less than the line you bet at, you have positive CLV. If the opening line is -3 and the closing line is -3.5, positive CLV. If the opening odds (for a moneyline bet) is +120 and the closing line is -105, positive CLV. If the opening line is +6 and the closing line is +7.5, negative CLV.

Get the idea?

The rule of thumb - If the closing line is less than the line you bet at, you have positive CLV.

Why CLV is important for improving as a bettor?

Winning bets and cashing tickets is a tell-tale sign you're doing something right. But believe it or not, it's far from the whole picture. And chances are if you aren't paying attention to your CLV, statistics say your luck will soon run out.

CLV enables bettors to have a more clear picture of how they will do in the long run, which is more important than the winning periods and losing periods we all experience as bettors.

Let's go back to that Cincinnati Bengals example. Let's say Cincinnati has a statistically worse-than-average game and ends up losing 35-28, meaning your +4.5 spread bet lost. Initially, most would consider this a bad bet because you lost money. However, if you followed your CLV, you would notice that it was positive because the closing line was +2!

What this means is although you lost this game, statistically speaking, it was a good bet, and over the long run of making similar bets, you would come out on top!

CLV enables bettors to have a more clear picture of how they will do in the long run, which is more important than the winning periods and losing periods we all experience as bettors.

How to calculate CLV for MLB/UFC/NHL bets, and ALL moneyline bets

Step 1 - Find the Win Probability for the line you bet at

Do this by taking the odds you bet at. If the odds are negative (i.e. -110) use this formula:

(a) Win Probability = Odds / (Odds - 100)

If the odds are positive (i.e. +130) use this formula:

(b) Win Probability = 100 / (Odds + 100)

Step 2 - Find the Win Probability for the closing line

Obtain the closing line from the Vault bet tracking app on the odds table, or anywhere you get odds from. Then, simply use the same formulas from above for the Closing Odds. If the closing odds are negative use this formula:

(c) Closing Win Probability = Closing Odds / (Closing Odds - 100)

If the closing odds are positive use this formula:

(d) Closing Win Probability = 100 / (Closing Odds + 100)

Step 3 - Calculate the CLV

Use the following formula for calculating CLV:

(e) CLV = 100 x ((Closing Win Probability - Win Probability) / Win Probability)

Example: You place a bet on the Milwaukee Brewers (MLB) spread -3 (-110), and the line closes at -2 (+105). First, calculate the win probability of your bet using formula (a) [ -110 / (-110 - 100) = 0.5238 ]. Then, calculate the closing win probability of your bet using (d) [ 100 / (105 + 100) = 0.4878 ]. Finally, calculate your CLV using formula (e) [ 100 x (0.4878 - 0.5238) / 0.5238 = -6.87 ]. So you had a poor CLV of -6.87% in this instance.

How to calculate CLV for NFL/NCAAF/NBA/NCAAB spread and total bets

Step 1 - Get the Win Probability for the line you bet at

Do this by taking the odds you bet at. If the odds are negative (i.e. -110) use this formula:

(f) Win Probability = Odds / (Odds - 100)

If the odds are positive (i.e. +130) use this formula:

(g) Win Probability = 100 / (Odds + 100)

Step 2 - Get the Win Probability for the closing line

Obtain the closing line from the Vault bet tracking app on the odds table, or anywhere you get odds from. Then, simply use the same formulas from above for the Closing Odds. If the closing odds are negative use this formula:

(h) Closing Win Probability = Closing Odds / (Closing Odds - 100)

If the closing odds are positive use this formula:

(i) Closing Win Probability = 100 / (Closing Odds + 100)

Step 3 - Adjust the closing win probability based on the line

This is the most challenging part of the whole process. If you're doing this for a lot of bets, I suggest setting up a bet tracking spreadsheet with formulas to do this for you as it will take a while. Or just have the Vault app do it all for you!

First you'll need to obtain push tables for all of these leagues. To make it easier, I've organized push tables here with values obtained from SBR's half-point calculator.

Here's an example of how to use this table to find the adjustment:

Let's say you bet on the Tampa Bay Buccaneers (NFL) spread at -12, and the closing line was -9.5. Go to the push table, in the 'NFL Spread' tab, locate the -12 spread. We then take 1/2 point "hops" until we get from the -12 probability to the -9.5 probability. To jump from -12 to -11.5, we take (0.0044/2 = 0.0022). Then, to jump from -11.5 to -11, we take (0.0222/2 = 0.0111). Then, to jump from -11 to -10.5, we take (0.0222/2 = 0.0111). We do this until we get to -9.5.

Finally, we add up all these adjustments and so the whole equation will look something like this:

Adjustment = (0.0044/2) + (0.0222/2) + (0.0222/2) + (0.0491/2) + (0.0491/2)

Adjustment = 0.0735

*Note, if a value is a spread or total value is outside of the range of numbers, then the probability as 0.

Now, use that adjustment and the Closing Win Probability you found in Step 2 to find the Closing Win Probability Adjusted. If the closing line is greater than or equal to the line you bet at, use this formula and add the adjustment:

(j) Closing Win Probability Adjusted = Closing Win Probability + Adjustment

If the closing line is less than the line you bet at, use this formula and subtract the adjustment:

(k) Closing Win Probability Adjusted = Closing Win Probability - Adjustment

Step 4 - Calculate the CLV

Use the following formula for calculating CLV:

(l) CLV = 100 x ((Closing Win Probability Adjusted - Win Probability) / Win Probability)

Let's be honest - calculating CLV isn't a walk in the park! There are a lot of calculations to make, especially if you're dealing with certain sports and bet types. But if you are serious about consistently improving as a sports bettor, finding your CLV is vital.

Thankfully, there are tools like the Vault app to help you track your closing line value for each bet, your CLV overall as a bettor, and even help you improve that CLV over time!

How to improve your CLV?

One of the easiest ways to improve your CLV, besides continually honing your skills, is to have 3-5 sportsbooks to line shop from when placing your bet. This way you can always find the most optimal line!

Finally, CLV gives a clear picture of when you need to make changes to your strategy, or when you need to keep persisting with your current one. Keep up with your CLV for all leagues and books, and make adjustments to your strategy when you see it dipping below 0% in order to continuously improve it!

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