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Poker glossary

Stack Size

What it means

Stack size is the number of chips a player has in front of them. In strategy discussions, the most important number is usually the effective stack: the smaller stack between the players who can still win or lose chips against each other.

How it works at the table

If you have 100 big blinds and your opponent has 40 big blinds, the effective stack is 40 big blinds. You cannot win more than those 40 big blinds from that opponent in the current hand. Against another player with 180 big blinds, your effective stack would be 100 big blinds.

Strategic context

Stack size shapes every decision. Short stacks create pressure and simplify all-in decisions. Deep stacks make position, implied odds, and postflop skill more important. Tournament stack sizes are often discussed in big blinds because blind levels keep changing.

Common mistakes

Players often think only about their own stack and forget the opponent’s stack. This leads to bad calls with speculative hands against short stacks and missed opportunities against deep stacks. Another mistake is using cash-game stack logic in tournaments where ICM pressure matters.

Stack size connects directly to SPR, short stack, big blind, and position. It also affects bluffing frequency, bet sizing, and how much pressure a player can apply.