Geometric Sizing

What Is Geometric Sizing?

Geometric sizing is a bet sizing strategy where each street's bet is calculated so that betting the same percentage of the pot on every remaining street results in exactly getting all-in by the river. Rather than choosing arbitrary bet sizes, geometric sizing provides a mathematically coherent framework that puts maximum pressure on your opponent's range while deploying your entire stack efficiently.

The Math Behind Geometric Sizing

The geometric bet size depends on the Stack-to-Pot Ratio (SPR). If the SPR is 4 with two streets remaining, the geometric bet size is the percentage of the pot that, when bet on the turn and again on the river (accounting for pot growth), uses your entire stack. The formula involves finding the bet fraction b that satisfies: (1 + 2b)^n = (Stack + Pot) / Pot, where n is the number of streets remaining. For most practical situations, the Geometric Sizing Calculator on ThinkGTO handles this calculation instantly.

Practical Example: Two Streets to Go

You are on the flop with $200 behind and $100 in the pot (SPR = 2). With two streets remaining (turn and river), the geometric bet size is approximately 62% pot on each street. You bet $62 on the flop (pot grows to $224), then bet roughly $139 on the turn (62% of $224), committing your remaining stack. This creates consistent pressure across both streets rather than betting small on one street and shoving the other.

Why Geometric Sizing Is Powerful

• Consistent pressure: Each bet forces your opponent to make a tough decision with their marginal holdings
• No awkward stack sizes: You never arrive at the river with an oddly sized stack relative to the pot
• Optimal for polar ranges: When your range is split between strong value hands and bluffs, geometric sizing maximizes the pressure on medium-strength hands
• Simplifies multi-street planning: One calculation solves your sizing for the entire hand

When to Use Geometric Sizing

Geometric sizing works best when you plan to bet all remaining streets with a strong value hand or a committed bluffing line. It is less appropriate for thin value bets where you want to control pot size. Postflop+ solver analysis reveals when geometric sizing aligns with GTO and when alternative sizing is preferred. For more on sizing strategies, read Bet Sizing Mastery: GTO Frequencies That Win Big Pots.