hand odds pre flop
bit of a stupid beginner question but I'm wondering about working the hand odds pre flop ... I know to caculate the % odds of the next (one) card you roughly double the number of outs in the deck and add one to get the percentage probability .. so this is good for the turn and river.
but in the case of the flop there are (three) cards coming .. so do I simply triple my one card result?
for example .. my pocket cards are 99 .. so the % odds of getting another 9 on the next card would be (two remaining 9's times two equals 4, and add one), which is about 5%.
so how to caculate this when you're about to see 3 cards?
all this is my beginner number wonking so any help and corrections are appreciated.
mike
but in the case of the flop there are (three) cards coming .. so do I simply triple my one card result?
for example .. my pocket cards are 99 .. so the % odds of getting another 9 on the next card would be (two remaining 9's times two equals 4, and add one), which is about 5%.
so how to caculate this when you're about to see 3 cards?
all this is my beginner number wonking so any help and corrections are appreciated.
mike
Comments
www.pokulator.com
might help...
The problem with multiplying out a 1 card result is it doesn't take into account you could have already hit your card. To illustrate, you can't hit 999 on the flop if you are holding 99 but that is what your simpler calculation would do. I believe the correct answer is about 12%. Approx 8 to 1 against. Note that this also includes the possibility of quads on the flop.
The odds of hitting one of the 3 cards exactly is the odds of hitting the first one and not the other 2 plus the odds of hitting the second one and not the other 2 plus the odds of hitting the third one and not the other 2. Or just calculate hitting it on the first card then multiply by 3 to handle each possible position.
((2/50)*(48/49)*(47/48)) * 3 = 11.5%
Your first formula is easy to use but it is a bit off. For calculating odds with 2 cards to come, a bit more accurate method is multiply your outs by 4 then subtract the number of outs over 9. If you had 15 outs after the flop, your odds to the river work out to 54%. The actual value is closer to 56%. For a single card to come, your calculation is not bad - I've seen double it and add 2 as being fairly accurate.
There are some good books out there and websites that will help. There are a number of threads on this site you should look at. Just search for 'odds'.
Good luck.
I'd seen some of the sites mentioned and some other places where the entire odds of making the draw from the pocket were given but not a lot specific to the flop.
spending some time with the texasholdem-poker.com caculator should give me some ideas as well.
I'm just trying to get myself in the ballpark at this point as I've a lot of other things to work through as well like the pot odds and position .. lot's to chew on and I just like general simple principles to build on.
again, thanks,
Mike
If you have a pair, odds against flopping a set are roughly 7.5 to 1.
If you have an unpaired hand, odds of flopping something (i.e. at least one pair) are roughly 2 to 1 against.
ScottyZ
Ok... you have 99... so there are 50 unknown cards left in the deck, 2 of which are the remaining 9s... so the odds of you getting a 9 on the <b>next</b> card are 2/50 or 4% (not 5%)
As pkrfce9 points out, tripling your 1-card result will get you close (3 x 4% = 12%), and close is usually good enough for calcs done at the poker table. Here's another method using combinations...
There are 50c3 = 19600 possible flops........ 50c3 is the number of ways to choose 3 cards from 50 when order doesn't matter. Nifty explanation link
Here's a breakdown of all possible flops that involve those 2 remaining 9s...
No 9s = 48c3 = 17296
one 9 = 2c1 * 48c2 = 2256
2 9s = 2c2 * 48c1 = 48
We see that 17296 + 2256 + 48 = 19600, so this accounts for all possible flops.
So given a pocket pair....
you flop quads 48/19600 = ~.2% of the time...
and a set 2256/19600 = ~11.5% of the time...
Nice post.