Expected value and fair price

What expected value actually means

Expected value (EV) is the average profit you would make per dollar staked if you could place the same bet thousands of times. It is a percentage of your stake — not of your bankroll, and not of your chance of winning. A bet showing +4.4% EV at a $50 stake has about $2.20 of expected profit in it. It does not mean you win 4.4% more often.

The number comes from one comparison: the price your sportsbook is offering against the price the bet is genuinely worth. That second number is the fair price, and every card in the Bet Feed prints both.

Odds are a probability in disguise

Any American price converts straight into a win probability. -110 means risking $110 to win $100, which implies a 52.4% chance. +150 implies 40%.

Now add up both sides of a real market. A book pricing a coin flip at -110 / -110 is quoting 52.4% and 52.4%, which sums to 104.8%. Those extra points are the vig — the book’s cut, built into the price rather than charged as a fee. It is the reason both sides of every market pay slightly less than they should.

Removing the vig to get a fair price

Devigging is stripping that margin back out. We take a benchmark market — one sharp book’s two sides, or an average of the other books covering that side — and rescale its probabilities so they sum to 100%. What is left is our estimate of the true chance.

Three standard methods (additive, multiplicative and power) are run on every market, and we deliberately keep whichever produces the lowest fair win probability for your side. That is the least flattering of the three answers, so the EV you see is the conservative one. Devigging explained walks through the arithmetic.

That probability, written back as American odds, is the figure beside Fair on the card. Next to it sits the benchmark it came from: a sportsbook logo when one sharp book supplied both sides, or (Avg) when an average of peer books did. Fair prices show on every card at every tier — only the EV% itself is gated.

The arithmetic, on one bet

EV is a single line: decimal odds × fair probability − 1. Take a card reading -105 at your book with Fair -115:

A 2.3-point probability edge becomes a 4.4% return on stake, because you are being paid at a longer price than the true chance deserves. On a $50 stake that is roughly $2.20 of expected profit — earned across a lot of bets, never collected on this one.

Turning an EV number into a decision

The feed is ranked by EV, highest first, so the biggest edge we can currently see is always at the top. You do not have to read percentages at all: every priced bet also carries a badge scored from its EV alone.

The suggested wager under a bet is Kelly sizing applied to that same edge — a bigger edge means a bigger stake. See How we size your wager. To put a floor under the feed instead, the Min expected value % inputs in Filters are covered in Bet Feed filters and saved presets.

What an EV number does not promise

• ●It is a long-run average, not a prediction. A +4.4% bet still loses often, and at longer prices it loses most of the time. EV describes the price, not the result.
• ●It assumes the price is still there. Books move lines constantly. Check the price on the slip before you confirm — if it has moved past fair, skip the bet.
• ●It is measured against our benchmark. Another site using a different book and a different devig method will print a different number for the same bet. Ours keeps the least flattering of the three devig methods.
• ●It is not income. Results arrive over hundreds of bets, with losing stretches in between that look nothing like an edge.