Find positive EV bets the moment prices move

A positive EV bet is a price that pays more than the outcome's fair probability says it should. Positive EV betting software finds those prices by computing a fair price for every line, comparing it with what each sportsbook is offering, and listing the gaps. The quant+ +EV scanner does exactly that, across sportsbooks and prediction markets, and shows you the math behind every row.

It doesn't tell you a bet will win. Most +EV bets lose a large share of the time. The point is the price.

What expected value means on a bet

Expected value is what a bet returns on average if you could place it thousands of times at the same price and probability.

The formula is short:

EV = (fair win probability × profit if it wins) − (fair loss probability × stake)

Everything hangs on the fair probability. If you use the book's own implied probability, every bet looks slightly negative, because the book's margin is baked in. So the scanner first removes that margin to estimate the fair probability, then runs the formula against every book's price.

A worked example

Say the sharp market on a game is -110 on both sides. Here is the arithmetic (an illustration, not a result).

Step	Side A	Side B
Price at the sharp book	-110	-110
Implied probability	52.38%	52.38%
Sum of both sides	104.76%
Fair probability, margin removed	50.00%	50.00%
Best price at another book	+110
EV per 100 staked at +110	0.50 × 110 − 0.50 × 100 = +5

At +110, a bet on Side A wins 110 for every 100 staked. If the fair chance really is 50 percent, the average result is plus 5 per 100, or 5 percent of stake. At -110 the same bet averages about minus 4.5 per 100. Same team, same game. The price is the whole difference.

How the fair price is estimated

Removing the margin sounds simple until the line is lopsided. On a -300 favourite against a +240 underdog, books tend to load more margin onto the longshot, so splitting the margin evenly overstates the underdog's chances.

A 2017 study in the American Journal of Sports Science compared four margin-removal methods on three large datasets. Plain normalization ignores that favourite-longshot pattern; the power method beat normalization and matched or beat the Shin method. quant+ weights prices from sharp books and removes the margin to produce one fair price per line, and the scanner compares every other book to that number.

Why use the market as the baseline instead of a model? Because market prices are hard to beat as forecasts. A 2018 PLOS ONE paper found that betting odds predicted results better than various quantitative models. An +EV scanner doesn't claim to know more than the market. It finds the books that are slow to agree with it.

How to read the scanner

Each row in the quant+ +EV scanner shows:

• Sport, game and market (spread, total, moneyline, player prop).
• Selection and venue: the side and the book or exchange with the price.
• Offered odds next to the quant+ fair price.
• Edge: the expected value at the offered price, as a percent of stake.
• A calculate button, so you can work the numbers on that row yourself.

Sort by edge, but don't stop there. Before acting on a row, check three things:

1. How old is the price? Open the line-movement view. A gap that just appeared after sharp books moved is a slow book. A gap that's been there for hours on a thin market may mean the fair price is the thing that's wrong.
2. How liquid is the market? Fair prices on main NFL sides rest on a lot of money. Fair prices on an obscure prop rest on much less.
3. What does it cost to get on? On prediction markets, fees come out of the edge. Polymarket's sports taker fee rate is 0.05 and peaks at a 50 percent price, so a thin edge on a coin-flip contract can disappear.

The limits you should know before you start

Variance. A 5 percent edge on a coin flip means you still lose about half the time. Long losing runs are normal even when every price is good. Judge yourself on closing line value, not on last week.

Account limits. Books restrict bettors who keep beating their prices. Three researchers who bet a market-based strategy with real money saw bookmakers cap their stakes within a few months, one to $10.45 on a $50 bet. Expect it, and spread your action.

Model risk. The fair price is an estimate. If you replace it with your own model, test that model honestly. Hubáček and Šír showed that a model can be less accurate than the market and still find value, if it's decorrelated from market prices, which is also a warning: a model that just copies the market adds nothing.

How quant+ fits into the workflow

The scanner is one panel of a terminal. Around it:

• The odds board, where you can see every book's price on the row you're looking at.
• Line movement, with the open, the close and every move.
• The bet journal, which grades each bet and records your closing line value, so after a month you know whether the scanner's prices were actually good for you.
• The backtest lab, if you'd rather test a filter (say, "only edges above a threshold on main markets") on past games first, with no look-ahead.

quant+ never places bets, holds funds or connects to your sportsbook accounts. You see the price; you decide. Read the risk disclosure before you use any of it.

Try it on one league

Pick one league and one market type. For two weeks, log every scanner bet in the journal and compare your price with the close. That tells you more than any headline number.

Start free to open the scanner, see an example on the home page, or read the quant+ guides on fair odds first.

Quant+ is analytics for informational purposes. 21+. If you or someone you know has a gambling problem, call 1-800-GAMBLER.