Pot odds calculation confusion

Hi Bitched63,
Welcome to PokerStrategy.com

It is surprising that something so fundamental can be so confusing, but you are not alone -- this question comes up frequently.
There is also a confusion introduced by the two different ways of expressing probability, which are:
  odds against This is the number of bad outcomes, a colon, then the number of good outcomes eg 4:1
  probability the percentage of the time that the good outcome occurs. If there 4 bad outcomes and one good outcome, there are 5 possible outcomes so the probability is 20% (1/5)

From the strategy article "The Basics: Odds and Outs"
Pot odds = possible reward : needed stake

In the aforementioned situation, the pot contains $8. You have to add the $2 that are placed by your opponent which makes a total pot and a possible benefit of $10. You have to pay $2 to stay in the game and see the turn card. Therefore the pot odds are $10:$2 or 5:1.

It might help to read the whole article.
In the situation quoted, there was a pot of $8, and opponent bet $2 thus requiring a call of $2

No mention is made of your own contribution, and based on the fact that Collin Moshman is one of the best SNG Coaches around, it appears that B is correct.

While you're here, be sure to check out the bonus offers or perhaps one of the free money offers

All the best,
VS

Hi VS.
Thank you for your reply.
In my example,
- to work out the percentage, it's CALL/ (POT+CALL) 100/(600+100) = 14.3%
- but the odds are POT:CALL 600:100 or 6:1
It seems that the confusion comes from inversing the percentage calculation to get to odds, which is wrong.
Anyway, it reassures me that you agree with me. What baffles me is the number of sites and apps that get it wrong. I bought a poker practice app on my phone today and can't even practice the pot odds section because the app fails me everytime
Take care
B

I agree you do not add your bet to the pot when calling.

I believe some of the confusion can be when there is more streets to come maybe ie. on the flop/turn. But I am not positive.

I personally use the pot/ the bet way on all streets.

Pot 500. Villlain bets 100.. me calling 600/100= 6/1. So I need min 20% equity to make a call.

It has worked for me.

Cheers

Mkablo, your calculation is correct. Interestingly however, I see that you write your odds 6/1 and not 6:1. This is something that I saw very often while researching this issue of working out odds. Using the / instead of the : may confuse some newbies and they could mix up 6/1 with 1/6. The latter is a fraction. For 6:1 odds ("chances that you will lose" to "chances that you will win") the fraction is 1/7 (1/total outcomes). Here's an example of a poker tutorial site where they write:

For example, if the total pot - including your opponent’s last bet - was $100 and you had to call a $20 bet then your current pot-odds are exactly 5/1. Pot odds are useful when working out whether your call has a positive expectation. In this example, assuming this was the final bet of the hand, then you simply need to work out whether you have a greater than 20% (1 in 5) chance of winning the hand. If you think this is the case then calling will show a profit over time if you think your chances are lower then calling will lose money over time and your hand should be folded.

Their odds are correct 5:1 .See how they use the / and not the :. Then they mention 20% and 1 in 5 chance of winning which is wrong. 5:1 = 1/6 = 16.7%. It's mind boggling the hours that such a mistake cost me.

A

Originally posted by Mkablo
So if you are to call you getting 100/20 or 5/1 which is 20% pot odds on a call.

When expressing odds normally a colon is used:
100:20 and 5:1 read this as "five to 1"
If a / is used in some cultures I guess I can live with that, since we live in one world. I still have to look twice when someone from Europe writes 53,125 -- is that fifty-three thousand one hundred and twenty five or 53 1/8
When expressing "odds" we show bad outcomes and good outcomes as a ratio of bad:good and in poker the "odds against" is assumed.
If you mean the other way around, you use "odds in favour"

Odds don't become probabilities by direct division.
5:1 means 5 bad outcomes and 1 good outcome.
So there are 6 possible outcomes, and the probability of getting the good outcome is 1/8 or 18% -- not 20% as so many sites seem to think according the OP

If you are given odds in the form of x:y then to calculate % probability you use 100 * (y/(x+y))
If the odds are 4:1 x+y is 5 and 1/5 is 0.2 and multiplied by 100 yields 20%

If you are given the probability as a percentage -- eg z% -- then to calculate odds you use ((100-z)/z):1
So if the probability is 20% then 100-20 is 80. Divide that by 20 and you get 4 -- so the odds are 4:1

When comparing pot odds (the amount you are getting for your bet) to drawing odds, it is important that you express the drawing odds as odds, not as percent, since the two measurements don't compare easily.

Sorry if that sounded a bit like a lecture.
Here is a link that explains it in far more detail
https://sphweb.bumc.bu.edu/otlt/MPH-Modules/BS/BS704_Confidence_Intervals/BS704_Confidence_Intervals10.html
in that link they use the actual word "to" instead of the colon for expressing odds -- or leave the "to one" part out.

Spot on VS. Thanks for the formulas.
5:1 odds = 16.7% (and not 20%) 4:1 odds = 20%

@Mkablo. 100/20 is 5:1 odds and 16.7% pot odds - not 20%. To convert pot odds x:1 to a percentage you have to work it out the way Vorpal explains so well.
If you are given odds in the form of x:y then to calculate % probability you use 100 * (y/(x+y))
If the odds are 4:1 x+y is 5 and 1/5 is 0.2 and multiplied by 100 yields 20%

👍 get it ty.