Put to the numbers, "Is value betting profitable?" begins with one idea. Value betting means backing a price that is higher than the true chance of the outcome deserves. The idea is simple to state and hard to use: every price carries the book's margin, so a bet has value only when the bettor's own estimate of the probability beats the price by more than that margin. Expected value is the arithmetic that says whether a given bet clears the bar or falls short.
How to calculate expected value betting in practice: turn the decimal odds into an implied probability by dividing one by the price, then compare it with the bettor's own estimate. Odds of 2.5 imply forty percent. If the estimate is forty five percent, the expected value is positive by roughly an eighth of the stake. The whole method rests on that estimate, which is where most value bettors slip.
Is value betting profitable? For a few careful and patient bettors, modestly and slowly, and for most, it never shows up at all. Is value betting legal? It is simply betting, legal wherever betting is, though books may limit or close accounts that win steadily. That limit is the real ceiling on value betting: an edge that the book notices tends to lose the stake size it needs to count.
How does value betting work across a season? Small positive edges add up only over hundreds of bets, and variance hides them for a long time. How to find value bets in sports betting comes down to knowing a market better than the price does: a narrow league, a player's fitness, a line that moved late. Lines on the biggest events are the sharpest, and value there is rare and small.
Short answers
What does closing line value measure?
Closing line value compares the price a bettor took with the final price before the start; beating it again and again is the clearest sign estimates are sound.
When does a bet count as real value?
Only when the bettor's estimate of the chance beats the price by more than the margin the book builds into it.
Why write the estimate down before seeing the price?
An estimate made after looking at the odds tends to drift toward them, and the whole value method depends on that estimate being honest.
Can variance hide a genuine betting edge?
Yes. A real but small edge can sit behind losing stretches for months, which is why short runs prove very little either way.
Should losing value bets be recorded too?
Yes. An honest record includes every bet, since dropping losers makes results look better and hides whether estimates actually work.