What is ‘Effective Stack’?
An Effective Stack is a poker term used to describe the smallest of the stacks between two players in a round of poker. The term is most commonly used when one larger stack goes against another smaller stack of a player who cannot put in as much money as their opponent has done.
This then means that the money in the smaller stack is the only one really at stake, making it the effective stack, as players can only lose/win what is in the smallest stack.
The term is only used when two players are left head to head to compete for a certain pot in a round of poker. For example, player A may go all in with a stack worth £50 but could only be called by player B who has a stack worth only £20. This would then mean that player A would only be able to lose £20 of their £50 and the excess £30 would be returned to player A should they lose as player A could only lose as much as player B had put in, rendering the excess £30 ineffective and makes player B’s stack the effective stack as it is the only stack which really matters in the round because it is the amount which both players could lose, regardless of whether player A went all in with more money.
The effective stack concept is used due to the fact that you cannot force a player to front more money than they are able to and when one player puts in more money than the other player could possibly front, the effective stack concept comes into play.