Pot odds calculator first, theory later. Villain bets, the pot is now $100, and it’s $25 to you. You’ve got a flush draw with one card to come. Call?
Put those three numbers in above and you’ll see it’s basically a coin you can’t win: you need 20% and a flush draw on the turn hits 19.6% of the time. Break-even, a hair below. Now swap the flush draw for a flush draw plus an open-ender (about 32%) and the same call makes you around $15 every time you make it. Same pot, same bet, completely different decision.
Reading the pot odds calculator
Pot size means everything in the middle including the bet you’re facing. People forget that part and get the wrong answer. Amount to call is what it costs you. Equity is your chance to win the hand, in percent.
Don’t know your equity? Count outs. Flop with two cards to come: outs × 4. Turn with one card to come: outs × 2. Rough, but good enough at the table. If you want the exact number, our poker odds calculator works it out from the actual cards.
The two formulas
Equity you need = call ÷ (pot + call) EV of calling = equity × pot − (1 − equity) × call
$25 into a $100 pot: 25 ÷ 125 = 20%. That’s the whole trick. If your equity beats that number, calling is profitable over time. If not, you’re paying for a lottery ticket.
Pot odds as a ratio work too. $100 to $25 is 4 to 1, so you need to win at least one time in five.
Where pot odds lie to you
They only see the money that’s in there now. Hit your flush on the river and you’ll often get paid a bit more. That extra is implied odds, and it’s why calling slightly light with a disguised draw can still be fine.
It cuts the other way too. If the board pairs and your flush might be no good, or the villain only keeps betting when you’re beat, the real price is worse than the number on the screen. Treat the result as the starting point, not the final word.
Bet size to equity, at a glance
You’ll see the same few bet sizes all night, so it’s worth knowing what each one asks of you:
| Opponent bets | You need |
|---|---|
| 1/4 pot | 16.7% |
| 1/3 pot | 20.0% |
| 1/2 pot | 25.0% |
| 2/3 pot | 28.6% |
| Pot | 33.3% |
| 2× pot | 40.0% |
A flush draw on the flop (about 35% by the river, if you’ll see both cards) can call anything up to a pot-sized bet. On the turn with one card to come it’s 19.6%, so a third of the pot is about the most you can pay.
Poker is a game of decisions over thousands of hands. Bet what you can afford to lose. If it stops being fun, BeGambleAware.org can help.