Free Tool

EV & ROI Calculator

Convert odds to a true probability and find out whether a bet is actually +EV — before you place it.

American oddsYour win %: 55%Stake ($)

52.4%

Implied prob

1.91

Decimal odds

+2.6%

Your edge

+$5.00

Expected value

ROI on this wager: +5.0%. A bet is +EV whenever your true win probability beats the odds’ implied probability (52.4%).

Reading expected value

Every set of odds carries an implied probability — the break-even win rate. American odds of −110 imply about 52.4%. If your real estimate of the outcome beats that number, the bet has positive expected value; if it doesn’t, the house edge wins over time.

Expected value is your average profit per bet if you could place it infinitely. Combine it with the bankroll calculator to size +EV spots without over-betting any single one.