The 4-2 Rule in No Limit Texas Hold 'Em

A Useful Formula for Calculating the Odds of Making a Better Hand

May 25, 2009

Many poker players use a formula called the "4-2 Rule" to determine the chance of catching a card they need to make a better hand than their opponent.

The “4-2 Rule” is very simple to calculate at the table, and you should make a habit of doing it when faced with a tough decision.

Definition of Pot Odds

In order to use the “4-2 Rule,” you need to know what pot odds are. Pot odds are simply the ratio of the amount of money in the pot to the amount needed to call a bet. For example, if there is $100 in a pot and Player A bets $50, Player B is getting pot odds of 3-1 to call (100+50=150) (150/50=3).

Back to the above example, if Player B is faced with this bet on the flop with a flush draw (Player B has four suited cards and he needs one more suited card to make a flush) should he call the bet? Here is where the “4-2 Rule” comes into play.

The "4-2 Rule"

There are 9 cards that can help Player B (13 total suited cards – 4 suited cards in Player B’s hand). These 9 cards are called “outs.” In order to figure out the percentage of catching one of those cards, you simply multiply the number of outs by 4 if the decision is on the flop (with two more cards to come) or 2 if the decision is on the turn (with one more card to come).

So in the example, Player B has 9 outs and the decision is on the flop so the formula is 9*4=36. That means Player B has a 36 percent chance of making a flush. The pot odds will help decide whether you should call the bet or not.

The pot is currently giving Player B 3-1 odds, which translates into 25 percent (here is an odds to percentage converter). The “outs” percentage must be higher than the pot odds percentage in order to justify making a call. Since 36 > 25, Player B should make the call.

When making the decision on the flop, you should only multiply your outs by 4 if you will be seeing both the turn and the river. If there is a possibility of a fold from Player B on the turn, he needs to multiply his outs by 2 instead of 4. By multiplying by 2, Player B is calculating the percentage of making his hand with one card to come rather than two.

In other words, you will usually multiply your outs by 4 when a player goes all-in on the flop and you need to decide if you are getting the right price to call. Otherwise, you will multiply your outs by 2.

This rule is not an exact science. Here is an odds chart that shows the actual percentages of making your hand with any number of outs. The actual percentage from the above example is 34.97 percent. However, it is relatively close to the 36 percent that the formula produced.

By using the “4-2 Rule,” you will be helping yourself to make better decision at the poker table, which in the end will help you be a winning player.

The copyright of the article The 4-2 Rule in No Limit Texas Hold 'Em in Poker is owned by Tom Mitsos. Permission to republish The 4-2 Rule in No Limit Texas Hold 'Em in print or online must be granted by the author in writing.

Sep 3, 2009 2:36 AM

Guest :

I believe there is an error in your first example. You stand to either lose 50 or win 100, therefore your pot odds are 2 to 1 (or 1 in 3) -- looks like you are saying they are 3 to 1. Rather than 25% as you state later in the example, should be about 33%.

Sep 3, 2009 5:31 AM

Tom Mitsos :

I'm calculating pot odds for Player B, not Player A. Player B has yet to make a bet. Player A has made the bet of 50, therefore Player B has to call 50 to win 150 (100 already in the pot + the 50 bet by Player A).