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Geometric Bet Sizing - What It Is And How To Use It

poker strategy Dec 22, 2022

In this article, you will discover what “geometric bet sizing” is and how to use this concept to boost your winrate.


Maybe you’ve already heard about geometric bet sizing before. In a poker video, the coach might have said something like: “This is a spot for Geometric Bet Sizing.”


But you were too shy to ask what it actually is. 


So I’ve decided to put together an article that will explain exactly what the concept of Geometric Bet Sizing is and how to implement it in your game.


But first, we’ll have to look at another concept called “Pot Geometry.”


What is Pot Geometry?


The concept of “Pot Geometry” refers to how the bet size on each street impacts the final size of the pot.


So, quite obviously, big bet sizes result in bigger pots, while small bet sizes result in smaller pots.


So far, so simple. Let’s examine two examples to see how bet sizing affects the final pot size. 


Example #1


You have AA on the BU, it’s folded to you, and you open to 2,5bb.


The Small Blind Calls. (Pot is 6bb)


Now, the board comes: 




You cbet 33% (2bb) and the sb calls. (Pot size is 10bb)


The turn is the Kh, so the board is: 




You bet 75%, and the bb calls. (Pot size is 25bb)


The river comes the 2c, so the board is: 




You bet 75% again, and the SB calls. 


The final size of the pot is 62,5bb.


The SB shows KsQs, and you take down the pot. Congratulations! 


Alright, what is important is that you keep the final pot size in mind as we look at our example number 2: 


Example #2


You have the same hand, and the preflop action remains unchanged, making the pot size 6bb going to the flop.


However, now, you’re not using a 33% (2bb) sizing; instead, you go for a bigger bet.

So, to refresh your  memory: You have AA, and the board is:




Now, you cbet 75% (4.5bb) instead of the 33% you’ve used before. (Pot size is 15bb)


SB calls, and the pot is 15bb.


At the turn comes the king of hearts, so the board is: 




You bet 75% again, and the SB calls, making the pot size 37.5bb.


The river, again, is the 2c, so the board is: 




You bet 75% again and get called by the SB, making the final pot size 93.75bb.


Based on this example, you can see that the final pot size is 31,25bb bigger by using a big bet!


You can already see how strongly early bet sizes affect the final size of the pot.

Now, let’s go to the core of this article.


What is Geometric Bet Sizing?

Geometric bet sizing means an equal bet size on each street needed to get the whole stack in at the end. 

You can use Geometric sizing in solvers to study which spots you should use this bet sizing scheme to maximize your EV.


 In Pio, you can use the term “e” for this. 


On the flop, “3e” means the same bet size over 3 streets. 


“2e” is the same sizing over 2 streets.


Let’s use our example to see which sizing would be geometric sizing here.


On the Flop, the pot is 6bb before we bet. 


Stack sizes are 97,5bb for both players. 


The SPR (=Stack To Pot Ratio) is at 16,25. 


This means we need to use 111% bet size on the flop and turn and river to get all in on the river.

  • Flop: 6bb + 111% *2 = 19,32bb 
  • Turn: 19,32bb + 111%*2= 62,21bb
  • River: 62,21bb + 111%*2= 200,31bb


You see that we don’t have the perfect percentage.


The reason for that is that we would need a more precise number, which is impossible to use in game.


However, a solver can quickly figure this out, and so can hotkey tools.


Alright, that’s it for today’s article. I hope you found it helpful and understand how to use geometric bet sizings for your studies now! 


As always, I wish you the best of luck at the tables!

And I think you would enjoy these articles as well: 


How to warm up your poker brain like a pro (click)

How solvers work (click)

5 tips on defending your big blind (click)


And if you want to dive deeper and start to go for the big bucks, check out our products in the store.