Rule 4 and 2

[rigor mortis]

Rule 4 and 2 is a misnomer, it is more accurately called Rule 2 (and sometimes 4). I read a thread where the writer multiplied his outs by 4 after the flop, which is wrong, and didn't even take the pot odds into consideration..
For those of you who like working inpercentages, here is how it should work.
The rule of 2 and 4 was coined by Phil Gordon in his "Little Green Book", and is a shortcut way of quickly working out the percentage odds of filling a draw in Holdem.
To get your percentage odds :-
Multiply your outs by 2 when on the flop waiting for the turn.
Multiply your outs by 2 when on the turn waiting for the river.
Multiply your outs by 4 when your opponent is all-in.
After you have worked out the percentage odds you must compare them to the pot odds to see whether or not it's worth calling a drawing hand.

 

[PaxMundi]

The rule of 4 and 2 is just a pure equity calulation.
Flush draw on flop = 9 outs - 9 x 4 = 36% chance
Flush draw on the turn = 9 outs - 9 x 2 = 18% chance
x outs by 4 on the flop and 2 on the turn. It's not an exact science it's a rough ad hoc way to do equity calulations on the fly. You can back up the assumptions by using poker tools like equilab away from the tables. It's not designed to take into account the pot odds that's a seperate calculation you need to do along with working out your equity.

 

[LanaRhoades]

Very interesting this rule.I think I will read more about it later.Thanks for the info.

 

[Izfensina]

That's the easiest way to calculate your Odds and Equity though I hate maths I find this rule very helpfull for early stages but once ITM I don't even dare to play most of my suited connectors Except Premium ones as I tend to play only monster draws not to bust on pure expectations cause when you flop a draw it's hard to lay down your cards face to aggressive players who hold already sets or Over pairs.

 

[rigor mortis]

The mistake most players make using this rule is this:
When facing a bet on the flop, do not multiply your odds by 4 unless your opponent is all-in.”
On deciding to call a bet on the flop when they are on a draw, most players will instinctively multiply their outs by 4. The reason is that they understandably think that they have both the turn and the river card to come. This is wrong.
This is wrong because you are in reality only getting to see one card from a call – the turn. After the turn has hit, you will then be faced with another round of betting, and may be forced to pay more to try and complete your draw.
It is only when the player moves all-in on the flop that you will get to see both cards without paying more!

 

[Cajin007]

Is it possible that phil was taking into account implied odds when he was talking about the 4/2 rule?
The All-in 4/2 would need extensive research into its validity, and I would be interested in the results.
Also, didn't someone revise the 4/2 rule recently to more accurately obtain the true percentages?

 

[sportswiz247]

Rule 4 and 2 is a misnomer, it is more accurately called Rule 2 (and sometimes 4). I read a thread where the writer multiplied his outs by 4 after the flop, which is wrong, and didn't even take the pot odds into consideration..
For those of you who like working inpercentages, here is how it should work.
The rule of 2 and 4 was coined by Phil Gordon in his "Little Green Book", and is a shortcut way of quickly working out the percentage odds of filling a draw in Holdem.
To get your percentage odds :-
Multiply your outs by 2 when on the flop waiting for the turn.
Multiply your outs by 2 when on the turn waiting for the river.
Multiply your outs by 4 when your opponent is all-in.
After you have worked out the percentage odds you must compare them to the pot odds to see whether or not it's worth calling a drawing hand.

I own a DVD that Phil put out years ago and in a section where he does the Rule of 4 & 2 it's different from what you mention here.

On the flop, with a potential flush draw, he calculates the outs by 4 which gives him a 36% chance of winning the hand and only after the turn does he do it by 2 which improves his hand to give him the flush as well as an open ended straight draw.

I have played it this way since even before I got the DVD and I feel that many people are using the rule wrong.

It should be noted that Kara Scott and Phil Hellmuth also have videos on You Tube that do it the same way as Gordon.

So the question has to be asked,"Are they doing it wrong?". Because from what you're saying in this post it seems to be the case.

 

[CallmeFloppy]

Yeah, I think there is some confusion around the concepts.

The rule of 4 and 2 is a simple way to understand your percentage depending on how many cards are left to come. But there are some additional things you need to factor in.

After the flop you have 2 more cards to come. If your opponent goes all in, you can multiply your outs by 4 since you are guaranteed to see both cards if you were to call. While not completely mathmatically accurate, it does get you close. If your opponent is not all in, you have to consider whether or not you are going to see both cards. If you are willing to draw down to the river, you can stick with 4 but need to consider additional bets and how that changes the equity of the hand. If you only plan to see one card, you would multiply the outs by 2, but need to consider the additional bets that may occur if you end up making your hand.

With all that said, I think the rule of 4 and 2 was really meant to be a way for beginners to get an idea of what there odds looked like if they played down to the river, not a full application of how to play the hand.

 

[Alizona]

since there are roughly 50 cards in the deck, each card that helps you to win the pot has a 2% of appearing on the next street since 1/50=0.02 which is 2%.

so when you have 9 outs, that means 9 cards can help you to take the lead on the next street, and each of those 9 cards has roughly a 2% chance of appearing... so 9x2%=18%, and this is why we have the rule of 2.

if you get to see 2 streets of action, which basically means you get all in on the flop to guarantee you will see both streets, then we double the chance because we do it twice... so this is the rule of 4 and our 9 outs chances is now 9x2%x2=36%.

these are rough approximations but they work perfectly okay when you're at a live poker table and don't have access to exact figures. But all of poker is an approximation, for instance, in this example, we can never be 100% certain that our 9 outs will actually win us the pot, sometimes they won't and they weren't really outs at all. But we follow this process every time, regardless. That's a separate skill from the math part of the game, that's the hand-reading part of the skill set.

 

[bigthereal]

thats a nice calculation

 

[NWPatriot]

A couple folks have hinted at this, but I want to provide additional clarity: the rule of 2/4 does not provide an Equity answer. It provides the probability that you will hit your outs. These are two different things.

If we have an Open Ended Straight Draw (OESD), we have 8 outs to hit our straight, or 16% chance per card. We do not have a 16% chance of winning the hand, which is generally how the term Equity is used. We may draw to the idiot end of the straight and loose to a better straight. We may loose to a flush. The point is to stop linking probability of hitting an out, to our equity. If we have a suited A, and are drawing to a flush, then we would have the nuts and our probability aligns better to our equity, as long as the last flush card doesn't pair the board giving our opponent a full house possibility.

We can only use the rule of 4 if we are guaranteed to see both the turn and the river - either because we will be all-in, or our opponent is all-in, or we are pot committed and will see both cards.

Semantics I know, but we need to make good decisions, and having a thorough understanding helps us do that.

Good Luck and God bless

 

[perrypip]

Yes its a common mistake the people make. On the flop you should consider your odds of improving on the turn not by the river when there is a future round of betting on the turn. If you use the rule of 4 and straight pot odds you won't consider the extra money you'll have to pay on the turn to get to the river.

 

[Collin Moshman]

Rule 4 and 2 is a misnomer, it is more accurately called Rule 2 (and sometimes 4). I read a thread where the writer multiplied his outs by 4 after the flop, which is wrong, and didn't even take the pot odds into consideration..

You don't need pot odds to calculate the percent change you'll hit a draw.

I do agree though that the rule of 2 and 4 isn't perfect, in particular it can really overstate your likelihood of hitting a large number of outs at the flop. There are ways to correct this, but even so, it's still a very nice guideline since it's simple to use and fairly accurate in most situations.

 

[Phoenix Wright]

As perhaps others have stated (directly or indirectly), this rule is just an estimate. It is extremely useful information, but it shouldn't be your only information; it should simply be a factor in deciding on your play. Here are a few simple scenarios where the "math" would be the same, but situationally it is NOT the same:

Using this rule, we estimate the change of us hitting our Flush draw with 2 cards to come. Say we have two hearts and the Flop has two hearts as well. The chance we improve to a Flush is the same regardless of what our hole cards are (as long as they are both hearts). However, I'm not going to value the nut Flush draw (Ahxh) identical to a weaker Flush like with hole cards of 7h2h

Using this rule of 2 and 4, the "math" of hitting the Flush is identical (roughly 36% by the river since 9*2 = 18% by Turn and (9*4 = 36% by River), but this is NOT the same as our hand equity like NWPatriot mentioned.

Another scenario factor to consider might be the kind of opponent we are up against. If we are against a TP (Tight-Passive) player, then we might be able to continue on a draw. What if the same situation came up with a sticky player who is aggressive AND on top of that, they are a good player? Do we want to be on a draw against them? Probably not. I'd be less inclined to continue with a marginal (or worse) holding against them because it is likely that they may raise more than I might like and they will force me off of my draw (remember that the entire calculation is only if you make it to the River).

Other factors to consider might range from villain personalities, pot odds, stage of the tournament (if it is a tournament, since cash games and other formats will come with their own nuances too).

The 2 and 4 rule is a great calculation to estimate hitting our outs, but it is NOT the same as equity and also NOT the only thing we should be considering in a hand. With this said, it is still a great estimate to make using very little effort/math to quickly get.