Poker Odds 101: Should I Stay or Should I Go?

This is the first in a series of articles that cover some very basic, fundamental poker concepts. If you’ve been playing for a while or have read more than one poker book, this is almost certainly refresher material. However, for the new folks around here that are just getting started and want to improve their game but haven’t read any of the books out there, the series should provide a little foundation for improvement. Don’t misunderstand, I consider poker books by David Sklansky to be the gospels of poker and these articles should not be considered a substitute for them. But if you’re starting out and aren’t quite ready to invest the time to read Hold ‘Em or Small Stakes Hold ‘Em or The Theory of Poker or (insert other poker book here) these articles should get you moving in the right direction regarding poker odds.

In Poker, every time it’s your turn to act you have 3 choices : Fold, Call, or Raise. Which is right? In this article, I won’t deal with the Raise option. This article will cover the basics of whether you are going to continue with a hand or not, and the math that should be used in such decisions. I’m not going to cover starting hands and preflop play. I will say this though, you should be playing tight and only playing solid starters. Look around the articles here, look at the message board, and find any beginning poker book and it deals with the preflop decision to fold/call/raise.

What I want to cover is the basics of “Should I Stay Or Should I Go!” from the flop forward. In order to make this decision you need to know 2 things : What are my Pot Odds and what are my Card Odds. If you know those two things you can make a “mathematically” correct decision about staying in the hand or not.

We’ll start with calculating Pot Odds. Pot Odds are very straightforward. Pot Odds is a ratio of the money you’ll get back from the pot compared to the size of the current bet.
Pot Odds = $ In Pot / Current Bet (expressed in ratio)
If there is $100 in the pot and the bet is $10 to you, you are getting Pot Odds of 10:1. Really, that’s all there is to it. If you are a limit player, I recommend that you keep track of this in Bets rather than $. Its easier to keep track of and it makes the switch from 1 level to the next easier. Preflop and flop, keep track of the bets as SmallBets (SB). When you get to the betting on the turn, divide the number of SB by 2 to get the number of BigBets (BB) and keep counting.

Example: You are playing $1/$2 limit and are on the button. 4 limpers to you, you raise, both the Small Blind and Big Blind call as do the 4 original limpers. 7 to the flop * 2SB each = 14SB. On the flop the first limper bets, the other 3 limpers call. You are now getting 18:1 Pot odds to call. But you’ve got a big hand so you raise. Both blinds fold, the bettor raises and all 3 limpers fold. You cap and the bettor calls. There are now 25SB in the pot (14 preflop, 4 from bettor, 4 from you, and 3 from limpers). On the turn the villain bets. What are your pot odds now? Remember, cut your SB in half so,
25SB = 12.5BB + 1BB = 13.5 : 1.

Lets move next to Counting Outs. 2 paragraphs barely scratch the surface of this topic. For a thorough exercise in being able to count outs, see Sklansky/Malmuth/Miller “Small Stakes Hold ‘Em” – Its got an entire chapter on finding “hidden outs.” I’m going to give the basics with a few “be aware of” things, but this certainly won’t make you an expert (keep in mind that I did not promise to do so). My definition of Outs is “Cards that will likely make your hand the winner at showdown.”

If you have 4 to a flush then you have 9 outs to make that flush.
If you have an open-ended-straight-draw (OESD) then there are 8 outs to hit that straight.
If you have a gut-shot straight draw then you have 4 outs to hit the straight.

None of that is news to you, I’m sure. But what about if you have a flush draw and 2 overcards to the board? Say you have AsKs and the flop comes Ts 4h 6s. How many outs do you have now? If an A or K comes on the turn your hand might be good. I usually count the cards that will pair my overcards as about 1/2 out each. This is not exact, but it is close. A lot of times the preflop action or flop action will tell you if this is true or not, but if you use 1/2 for each overcard you won’t be too far off. So, in this hand I have 12 Outs (9 flush cards + (1/2 * 6 A/K left).

What about if I have an OESD and there are 2 cards of the same suit on board? How many outs is that? Again, a lot depends on the read you have of your opponents, how many opponents are left in the hand, and action preflop and on the flop, but I want to give you something to start with that you can refine with more reading and more experience. Lets say that you have JhTd and the flop is Qs Ks 6c. So you have 6 outs to the nuts (three non-spade 9 and 3 non-spade A). But you can’t just eliminate the 9s and As because its not a certainty that someone is on the flush draw. So the As and the 9s can be treated as half-outs as well. Again this isn’t exact but it is a good approximation unless the betting tells you that someone is on a flush draw. So you have about 7 outs (not likely that pairing your J or T is going to be good). Lets say you have pocket Aces (yippie!). There are 2 villains (one is the BB who protected against your raise) in the hand against you. On the flop, the BigBlind comes out betting, villain 2 folds, you raise and BigBlind reraises. You suspect that villain has 2-Pair. How many outs do you have against his 2 pair? You have the two other aces in the deck, and for the turn you have three outs to pair the board (of the card he didn’t pair). So you’ve got 5 outs now, and assuming that he doesn’t hit his full house on the turn, you’ll have 8 outs on the turn. Whether or not to call depends on the pot odds and what we calculate the card odds to be, but just make sure that you count all your outs!

Card Odds : Card Odds is a description of the probability that any of the card(s) that you need to make the best hand will come. It is expressed as a ratio where the first # represents how often it WON’T happen against how often it will happen. It is generally expressed as N : 1.

Card Odds = (#unseen cards – Outs) / Outs (expressed as a ratio). So if you have a flush draw on the flop, you have 9 outs. 47 unseen cards after the flop (52 – 2hole cards – 3 flop cards = 47). Odds that you’ll hit your flush on the next card = (47-9) / 9 = about 4:1. That’s all there is to this as well. It’s not tough, it just requires some practice.
Flop an OESD, what are your card odds to hit the straight on the turn? 8 outs, so COdds = (47-8)/8 = 4.875 (or about 5:1)

There are plenty of charts out there that show card odds for 2 – 25 outs. I’m not going to include one here for the sake of brevity, but now you know how to do the calculation yourself.

Card Odds vs. Pot Odds : Should I continue with this hand? That is the eternal question in Poker. How many times have you thought “I don’t think I’m ahead, but man if I can just catch that (fill in card need here) I can take this pot down!!!” I do it all the time. I hate folding. I prefer action! Most people do. But I like winning money more than I like action, so before I toss more chips into a pot hoping to catch my 2 outer I do the math to determine if I should or not. The most basic way to determine if you should continue in a pot or not is this : Are the odds I’m getting from the pot bigger than the my card odds? If the answer is “yes” then you should continue in the hand. If the answer is “no” then you shouldn’t continue in the hand (there is exception to this that deals with something called “implied odds” that I’ll discuss in a later article). Lets look at an OpenEndedStraightDraw (OESD). Here is the scenario:

You are in the BB with J8o. 4 players limp (including the SB) and you check. (5players, 5SB to the flop). The flop comes (Ts 3c Ah). It gets checked around and the turn comes 9d. So now there are 5 players and 2.5BB in the pot. The SB checks, you check and 1st limper bets. All limpers call (including the SB) and its up to you to act. What do you do? The pot is now offering you 7.5:1 odds (2.5BB + 5BB = 8BB). The odds that you’ll hit your OESD are about 4.75:1. This is a CLEAR call.

Lets change it a bit though to show a fold. Lets say that when Limper 1 bets, everyone folds to the button who raises and the SB folds. What are your pot odds now? 2.5BB + 1 + 2 = 5.5BB in the pot, but its going to cost you 2BB to call, so you are only getting 2.75 : 1 pot odds. The odds of hitting the OESD are still 4.75 : 1, so this is a fold (NOTE : Its possible that Implied Odds could make this a call, but that is for a later article).

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