Understanding poker EV (expected value)
Expected value, or EV, is the average result of a decision if you could repeat it an unlimited number of times. In poker, EV tells you whether calling a bet makes money over the long run, even though any single hand can still win or lose regardless of whether the call was correct. A decision with positive EV is profitable on average; a decision with negative EV loses money on average, no matter how the current hand turns out.
The formula
For a call, the standard formula is:
EV(call) = (Equity × Amount Won) − ((1 − Equity) × Amount Lost)
Where Equity is your probability of winning the hand at showdown (as a decimal), Amount Won is the net profit if you win — the pot that was already there, since the money you put in to call comes back to you — and Amount Lost is simply the amount you called. If rake is taken from the pot, it reduces the amount you actually collect when you win, so Amount Won = (Pot + Call) × (1 − Rake) − Call.
Pot odds and breakeven equity
Pot odds compare the size of the pot to the cost of calling, written as a ratio like 4:1 (a $100 pot facing a $25 call). Converting that ratio into a percentage gives the breakeven equity — the exact win probability at which EV equals zero:
Breakeven Equity = Call ÷ (Pot + Call)
If your real equity is above this number, calling is profitable (+EV). If it's below, calling loses money on average (−EV), even if you sometimes win the hand. With a $100 pot and a $25 call, breakeven equity is 25 ÷ 125 = 20%; any hand you expect to win more than 20% of the time is a profitable call.
Worked example
Pot is $100, you must call $25, and you estimate 35% equity. Amount won if you win = $100 (the existing pot; your $25 returns to you). Amount lost if you lose = $25. EV = (0.35 × 100) − (0.65 × 25) = 35 − 16.25 = +$18.75. Since your 35% equity clears the 20% breakeven threshold by 15 percentage points, this is a solidly profitable call.
Why one hand doesn't prove the decision right or wrong
EV describes an average across many repetitions, not a guarantee for this hand. A +EV call can still lose the pot, and a −EV call can still win it. Judging a decision by a single result — instead of by the equity and pot odds available at the time — is one of the most common mistakes in poker strategy.