# 2-4 rule?

• Bronze
Joined: 10.11.2007
(a)

The probability of hitting one of the players outs with the next community card is around 2% * number of outs + 2%.

(b)

The combined probability of hitting one of the players outs from the flop either with the turn- or river card is around 4% * number of outs (-1% with 9-12 outs and -4% with more than 12 outs).

I was wondering if someone could give me an example of both (a) and (b) respectively, especially (b) with the bracketed area on the end of the equation eg. what about less than 9 outs like 8? or 7? etc.....
• 4 replies
• Bronze
Joined: 10.11.2007
I had always multiplied my outs by 4 for the turn and by 2 for the river

eg.

I have an OESD on the flop and 8 outs so : 4 x 8 = 32% (roughly)

and after the turn card : 2 x 8 = 16% (roughly)

is this ok?
• Bronze
Joined: 21.09.2007
Well, thats not right, but it's close. You can count it easily

the OESD on the turn + river = 8/47 + 8/46 = 34.4%
and the OESD on the river only is 8/47 = 17.4%

If you want to quickly estimate the probablity then multiply by 2 and add 1%. Hower I think that the best way would be to use odds estimates. e.g. OESD is about 4.9-1 underdog on the turn or river (which is why you need 5-1 pot odds to call), and it is a lot easier to compare it to the pod odds, which in fixed limit are very simple to count.

http://www.pokerstrategy.com/strategy/fixed-limit/173/1/
• Bronze
Joined: 26.08.2007
The rule of 4 and 2 is a very quick and easy way to estimate your chances of hitting your draw. Just be careful to use the rule of 2 on the flop if you're intending to fold the turn unimproved.
• Bronze
Joined: 10.11.2007
I was wondering if someone could give me an example of both (a) and (b) respectively, especially (b) with the bracketed area on the end of the equation eg. what about less than 9 outs like 8? or 7? etc.....

an example would be really awesome if could annoy someone a bit more pls