Effective stack
The smaller of the two stacks in a hand — the most that can be won or lost between those players. All strategy calculations use the effective stack, not your own.
Frequently asked questions
What is the effective stack in poker?
The most that can actually be won or lost in a hand — the smaller of the two stacks involved. If you have 200 big blinds and your opponent has 30, you are playing a 30-big-blind pot, whatever your own stack says.
Why does it matter so much?
Because the whole shape of a hand depends on it. Deep stacks make implied odds, set mining and multi-street play valuable; shallow stacks make high-card strength and the ability to get all in matter instead. Reading your own stack rather than the effective one is a common and expensive mistake.
How does it work multiway?
It is calculated separately against each opponent, so you may be deep against one and shallow against another in the same pot. The smallest relevant stack usually dictates how the pot plays out, since that is the player who will be all in first.