BB to stack size ratio

Question

Morning All, Why is only the Big Blind used in measuring stack size? It ignores the effect of the Small Blind and antes in each round of play, If you have 20 BBs you only have 12.5 rounds of play before being blinded out. I realize formats have changed somewhat, still curious about the BB to stack size ratio reasoning.

Answer 1

Since small blind is often just half a big blind, its effect is implicitely taken into account.

For games with antes, you may want to learn about Harrington's M (ratio between stack and initial pot)

Answer 2

The reasoning behind BB being used as a measuring unit of stacks is three-fold:

1. It is stake-agnostic. No matter the stake, you can easily perform measurements and analytics of most hands, players and games in relation to their BB or BB/100. Additionally, it allows us to abstract theory and develop technique that can then be practically transferred to almost any other stake. This is especially useful in conditions where the blinds change.
2. It is the minimum possible raise on any street. Not even the small-blind can raise 0.5BB. For them to perform a raise, they must pay a minimum of 1.5BB (if no other player has raised). This makes it the most recognizable unit.
3. Since it is stake-agnostic and the minimum possible raise, this allows it to utilized across most formats, as well, whether they involve cash or not.

It's also important to note that it can (and is in some cases) also used to measure bets, pots and profitability. If one learns to think in terms of BB, they can then compare, contrast and further inform their performances across stakes and formats. And this is true whether or not they theorize and share or not.