M Factor and the Zone System

A basic feature in Multi Table Tournaments (MTTs) or tournaments Sit and Go (SnGs) is the increase in forced bets (blinds and antes). The logic behind this increase is natural: to force players to take risks so as not to be eaten by the blinds.

But then some questions arise:

  • When can I say that my stack is good relative to the blinds?
  • When should I actually enter push/fold mode?
  • A short stacked villain pushed all in preflop. Based on his stack size and the range he would make this move, should I call or fold?

All answers can be given using one of the most (if not the most) important concepts for tournaments, the M Factor.

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It had been used in poker for quite some time, without a proper name, until Paul David Magriel Jr. started calling it the M Factor, and the name stuck.

This concept was developed in detail by Dan Harrington and Bill Robertie in the book “Harrington on Holdem (Vol. 2): The Endgame”. The authors state that the M Factor is “the most important index that governs your game until the end of a tournament“They emphasize that this number is crucial, and we must develop the ability to quickly calculate it.

Factor M is given by:

Therefore, it is the division of the stack by the pot pre-flop before any betting.

Two calculation examples:

1) Stack of 3,000 chips and blinds of 100/200. Therefore M = 3000/(100+200) = 10

2) Stack of 6,750 chips and blinds of 250/500/50, and the table with 10 players, we have M = 6750/(250+500+50*10)= 5.4

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The number of players modifies the effectiveness of this number, so Harrington proposes a correction depending on the number of players at the table, called M effective:

Ok, we now know how to calculate the M-Factor and make the necessary corrections based on the number of players. But how can we use it?

Like all poker concepts/theories, we must always adapt to the situations presented at the table. Even so, some basic guidelines are important for us to make good decisions more often than not. In this sense, it is proposed to divide the M Factor into 5 zones:

Always keep in mind your M Factor and that of your opponents, adapting to each situation!

And good luck!

Revised/reposted in May/2016.

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20 COMMENTS

    • “Complex moves” are actions that involve risking a lot of chips. For example, an opponent raises 3xBB and you re-raise 9xBB as a bluff. In this case, you are risking a lot of chips, which should be avoided when you are in the orange zone.

  1. Hi, professor. Question: for the zones (strategies), should M effective be considered? And regarding the number of players, do I consider them for each hand (removing those who fold from the count) or the participants at the table (by which I have already multiplied them before)?

    Big hug!

  2. A question

    If my stack is 28k, at a table with blind 400/800 ante 75

    calculating M we have: 28,000/1275 = 21.96

    here we have effective M: 21.96* 9 players / 10 =

    M effective = 19.76 ? = Yellow zone

    is that right?

  3. Sorry to intrude here, friend Petrillo, but Mandrak is only considering 1 before.

    If you are at a table with 9 players, the correct count would be: 28,000 / 1,875 = 14.9, wouldn't that be it?

    In the text about the correction of the M factor this is not very clear.

    I understand that the table is for 10 players, but that “at the moment” it only has 3, 4, 5. The correction of the M factor would then be for each moment of the table, which could return to 10 at any time, wouldn't that be it?

    Hug!

    • You commented before Thiago, he had his comment replied and you didn't. That seems a bit strange to me. And you are absolutely right in your comment.

  4. Very good article, but... I think the calculation for example 02 is wrong!

    M= 6750/ 250+500+50 => 8.43 = 8.4
    Me= 8.4* (players/ 10) => 8.4 * (10/10) => 8.4*1 = 8.4

    Wouldn't that be it!?
    Abs…

  5. Hi Thiago! Thanks for the kind words!

    In fact, Example 2 is correct. Look carefully at the formula. You must add up the antes of all players. In your account, you only added one ante (50 chips), instead of 10 antes (500 chips), since in the example we have 10 players at the table.

    So the calculation is as shown: M = 6750/(250+500+10*50) =5.4 (note that you put (250+500+50) in the denominator).

    Thanks!

  6. in the Stack part of 6,750 chips and blinds at 250/500/”50” those 50 at the end are what you want???
    I await your response, thanks ;]

  7. I don't see any difference between using the number of big blinds and the “M” factor to calculate the stack size.(?)
    In fact, calculating the stack using the number of big blinds is much more practical. Did I miss some detail?

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