Measure of the health of a player's chip stack in poker
In no-limit or pot-limit poker,
a player's M-ratio (also called 🔑 "M number", "M factor"[1] or just "M") is a measure of
the health of a player's chip stack as a 🔑 function of the cost to play each round. In
simple terms, a player can sit passively in the game, making 🔑 only compulsory bets, for
M laps of the dealer button before running out of chips. A high M means the 🔑 player can
afford to wait a high number of rounds before making a move. The concept applies
primarily in tournament 🔑 poker; in a cash game, a player can in principle manipulate his
M at will, simply by purchasing more chips.
A 🔑 player with a low M must act soon or be
weakened by the inability to force other players to fold 🔑 with aggressive raises.
The
term was named after Paul Magriel.
Calculation [ edit ]
The M-ratio is calculated by
the formula:
M = stack 🔑 small blind + big blind + total antes {\displaystyle M={\frac
{\mbox{stack}}{{\mbox{small blind}}+{\mbox{big blind}}+{\mbox{total antes}}}}}
For
example, a player in an eight-player 🔑 game with blinds ofR$50/$100, an ante ofR$10, and
a stack ofR$2,300 has an M-ratio of 10:
M = 2300 50 + 🔑 100 + ( 10 × 8 ) = 2300 230 = 10
{\displaystyle M={\frac {2300}{50+100+(10\times 8)}}={\frac {2300}{230}}=10}
That is,
if the 🔑 player only makes the compulsory bets, he will be "blinded out" of the game in
10 rounds, or 80 hands.
Dan 🔑 Harrington studied the concept in great detail in
Harrington on Holdem: Volume II The Endgame, [2] defining several "zones" in 🔑 which the
M-ratio may fall:[3]
Zone name M-ratio "Optimal" strategy Green zone M ≥ 20 Most
desirable situation, freedom to play 🔑 conservatively or aggressively as you choose[4]
Yellow zone 10 ≤ M < 20 Must take more risks,[3] hands containing small 🔑 pairs and small
suited connectors lose value Orange zone 6 ≤ M < 10 Main focus is to be first-in
🔑 whatever you decide to play, important to preserve chips Red zone 1 ≤ M < 6 Your only
move is 🔑 to move all-in or fold Dead zone M < 1 You are completely dependent on luck to
survive. The only 🔑 move is to push all-in into an empty pot
Effective M [ edit
]
Harrington further develops the concept to account for 🔑 shortening tables, as is seen
at the closing stages of multi-table tournaments. The M-ratio is simply multiplied by
the percentage 🔑 of players remaining at the table, assuming a ten-player table to be
"full". [5]
M Effective = M × ( Players 🔑 10 ) {\displaystyle
M_{\mbox{Effective}}=M\times \left({\frac {\mbox{Players}}{10}}\right)}
Therefore, for
a player with a "simple M ratio" of 9 at a five player 🔑 table, the effective M is 4.5:
M
Effective = 9 × ( 5 10 ) = 4.5 {\displaystyle M_{\mbox{Effective}}=9\times \left({\frac
{5}{10}}\right)=4.5}
This 🔑 means that although the player's simple M value places him in
the orange zone, his effective M dictates a shift 🔑 in playing style appropriate for the
red zone. In essence, ten times the effective M denotes the expected number of 🔑 hands a
player can let pass before running out of chips.
See also [ edit ]
