Quick MTT bubble math

Dara O Kearney
Dara O’Kearney

Those of you who read my first book will be familiar with the term “gorilla maths” to describe a simplified version of complicated maths that can be done at the table as an approximation for satellites.

In regular tournaments ICM is a complicated calculation of how many times a player comes 1st, how many times they come 2nd when another player comes 1st, and so on. In a satellite ICM is practically a calculation of how often all the players can mincash, so it is much easier to simplify satellite math.

Having said that, I am now going to explain a gorilla maths method for determining ranges on the bubble of a regular tournament.

Say we have a 500 runner tournament that pays 60 players, and the mincash is 2 buy-ins.

That means with 60 players left, everyone in the field is guaranteed a 2 buy-in mincash (120 buy-ins in total shared between 60 players), and their “share” of the remaining prize pool (380 buy-ins total yet to be won) is in direct proportion to their share of the chips. This is a simplification. Usually the big stacks have a slightly smaller share of the pool than their chips, and the smaller stacks a bigger share, but it’s close, and we are not computers that can calculate exactly so we just want a decent approximation.

Gorilla Math

Dara O Kearney

So the equity of someone who gets through the bubble with a starting stack can be calculated as:

  • 2 buy-ins (the guaranteed min cash)
  • Plus One 500th of the other 380 buy-ins (.76 buy-ins)

Total 2.76 buy-ins.

The equity of a player with 2x starting stack using the same method is equal to 3.52 buy-ins.

That means if a player with starting stack gets it in on the bubble they are risking 2.76 in buy-ins in equity to gain .76.

2.76/(2.76+0.76) = 78%

So he needs to be 78% favourite roughly. Here’s the equity of strong hands versus different ranges:

Against any 2 cards

  • AKs 67%
  • AKo 65
  • AA 85
  • KK 82
  • QQ 80
  • JJ 77

So even Jacks not a get in here on the bubble despite being up against a 100% range.

Against top 20% of hands

  • AKs 64%
  • AKo 62%
  • AA 86%
  • KK 72%
  • QQ 69%
  • JJ 66%

Here we need Aces!

It’s not perfect but we roughly get to the same outcome that a solver gives us in these spots. Try it out for yourself and let me know how you get on.

If you want more insight like this, Dara has a regular newsletter where he gives free tips like this all the time.

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