Tools · Calculator
Expected Value
Compare the price you're getting against the fair, no-vig price. The gap between them is your edge — this turns it into expected value: how much each bet is worth, as a percentage and in units.
The Bet your price vs the fair price
How expected value works
The no-vig price tells you what's truly likely; your price tells you what you're paid. Expected value is the distance between them, expressed as profit per bet over the long run.
The no-vig line
Books bake a margin into every price. Strip it out — the fair / no-vig odds — and you get the market's true estimate of the outcome. Its implied probability, 1 ÷ fair decimal, is your true win probability.
The formula p · d − 1
Take the true probability p from the fair line, multiply by your decimal odds d, subtract 1. That's EV per unit. Positive means your price pays more than the true risk — value in your favour.
Edge & break-even
Your odds imply a break-even win rate of 1 ÷ your decimal. Your edge is the true probability minus that break-even. Whenever the fair line is longer than your break-even, the bet is +EV.
The long run
EV is an average, not a promise — a +EV bet still loses often. A small percentage edge only becomes real profit across volume: the per-100-bets figure is what survives the variance.