How this instrument works
Expected value, or EV, is the average result of a poker decision if you made it over and over across many identical situations. A single hand's outcome is random — you either win the pot or you don't — but EV weights both outcomes by their probability to tell you whether a call, bet or fold makes money on average over the long run, which is the only timeframe that actually matters for a poker strategy.
This instrument calculates the EV of calling a bet: it multiplies your probability of winning the hand by the pot size (what you gain if you win), then subtracts your probability of losing multiplied by the amount you're risking (what you lose if you don't win), and adds the two together. A positive result means the call is profitable in the long run even though you might still lose this particular hand; a negative result means the call loses money on average even if it happens to win this time.
EV is the mathematical backbone behind concepts like pot odds and outs: once you know (or estimate) your probability of winning — often from counting outs, as in this site's poker-odds instrument — plugging that into an EV calculation tells you concretely whether the numbers justify a call, independent of gut feeling or how the last few hands went.
- Enter Probability of winning the hand as a decimal between 0 and 1 (0.35 means a 35% chance to win).
- Enter Pot size — the total chips in the pot that you'd win if your hand holds up.
- Enter Amount you must call/bet — the chips you're risking on this decision.
- Read Expected value (EV) for the result: positive means the call is profitable long-run, negative means it loses money on average, and zero is exactly breakeven.
- Win probability must stay between 0 and 1 — use decimals like 0.35 for 35%, not whole percentages.
Worked example — 35% equity, 200-chip pot, 50-chip call
Enter 0.35 for Probability of winning the hand, 200 for Pot size, and 50 for Amount you must call/bet. The win term is 0.35 x 200 = 70, and the loss term is (1 - 0.35) x 50 = 0.65 x 50 = 32.5.
Expected value (EV) = 70 - 32.5 = 37.5. This call is worth calling on average: even though this particular hand only wins 35% of the time, the pot is large enough relative to the call that the decision nets an expected 37.5 chips every time you make it in this exact situation, across many repetitions.
Questions
What does a negative EV mean?
A negative EV means that, on average across many repetitions of the exact same situation, the call loses chips even though you might still win this individual hand. Winning a hand with negative EV doesn't retroactively make it a good decision — the math is about long-run profitability, and consistently making negative-EV calls will lose money over time even with occasional lucky wins.
Where do I get my win probability from?
It's usually estimated by counting your outs (cards that improve your hand to a winner) and converting that to a probability, either with an exact hypergeometric calculation or a quick shortcut like the poker 'rule of 4 and 2.' This site's poker-odds instrument calculates that probability directly from your outs and cards remaining, which you can then plug into this EV calculator.
Why subtract the loss term instead of just using pot odds?
Pot odds compare the size of the call to the pot without folding in your actual win probability, giving you a breakeven percentage to beat. EV goes a step further and gives you an actual expected chip result once you supply your real (or estimated) win probability — it answers 'how many chips, on average' rather than just 'is this above or below breakeven.'
Does a breakeven (EV = 0) call matter?
A breakeven call neither gains nor loses chips on average, so purely by the numbers it's indifferent to calling or folding. In practice, many players lean toward calling breakeven spots because of implied odds (extra chips won on future betting rounds if you hit) that this simple formula doesn't capture, though that's a judgment call beyond the raw EV number.
Can I use this for a bet instead of a call?
The same formula structure applies to any decision where you risk a fixed amount to win a pot with some probability of success, whether that's a call, an all-in shove, or a bluff you expect to work a certain percentage of the time. Just make sure Amount you must call/bet reflects what you're actually risking in that specific decision.