Expected Value Calculator

Estimate the long-run dollar outcome of a bet given your probability estimate and the offered American odds.

Inputs

Bet amount (USD)The dollar stake on this bet.

Odds (American)Example: -110 for a standard line, +120 for an underdog.

Your estimated win probabilityYour honest estimate, 0 to 100.

Result

Expected value$0.00

Expected ROI0.00%

Implied probability (from odds)50.00%

Edge (your prob − implied prob)0.00%

Profit if you win$100.00

What this means

This bet is break-even. The odds match your probability estimate; you would neither gain nor lose money on average.

Formula

EV = (win_prob × profit_if_win) − ((1 − win_prob) × stake)

decimal_odds = (odds / 100) + 1     if odds ≥ 0
             = (100 / −odds) + 1    if odds < 0
implied_prob = 1 / decimal_odds
profit_if_win = stake × (decimal_odds − 1)

Expected Value: The Only Metric That Matters Long-Term