POSTFLOP · FIELD NOTE
Geometric Bet Sizing: How to Set Up a River Shove
Choose equal-percentage bets that put the stack in by the river, understand the underlying pot geometry, and know when not to use it.
You flop a strong hand and want to play for stacks by the river. If you bet too small now, the river shove may be enormous. If you bet too big, you can chase away the hands you want to call. Geometric sizing gives you a useful starting size.
The short answer
Choose the same percentage of the pot on each remaining street so the last bet uses the rest of the effective stack. Treat that number as a baseline, then adjust when the board or ranges prefer a different size.
Three useful words
Geometric sizing means betting the same percentage of the pot on each remaining street. Pot geometry describes how each bet grows the next pot. Effective stack is the smaller stack that can actually go in.
Two quick examples
- Reasonable: The pot is 10 big blinds (10bb) with 30bb behind and two streets to play. Repeating roughly 82% pot uses almost the whole stack: about 8.2bb now, then the remaining 21.8bb into a pot near 26.4bb.
- Not reasonable: You force that same size on every possible turn and river. A river that completes a flush may change which player has enough strong hands to shove, even if the arithmetic is tidy.
Practice this spot first
With aces on K-7-2, estimate the repeated bet size that gets all-in by the river. Then decide whether this dry board really wants that size on every street.
Understand the growth
When you bet a fraction b of the pot and receive a call, the next pot becomes P × (1 + 2b). Repeating the same fraction grows the pot geometrically. The correct fraction depends on the starting pot, effective stack, and number of betting streets remaining.
Use a calculator in study rather than forcing mental algebra at the table. Memorize common SPR patterns after seeing them repeatedly.
Calculate from effective stacks
Only the amount both players can wager matters. If one player has 80bb behind and the other 150bb, plan around 80bb. Include the current pot accurately; preflop sizes and dead money change the result.
Treat the answer as a baseline
Geometric sizing answers, “What equal percentage gets the stack in?” It does not answer, “What size earns the most?” A dry flop may work better with a small bet followed by larger turn and river bets. A turn that creates many draws may call for a larger bet right away.
Build value and bluffs for each street
Make sure you have enough value hands and sensible bluffs for every planned bet. Your value hands must stay strong on many turn and river cards. Your bluffs need equity, useful blockers, or cards they can keep betting. If a turn strongly favors your opponent, abandon the plan you calculated before seeing it.
Avoid awkward leftovers deliberately
Thinking geometrically helps you avoid a turn bet that leaves a tiny river stack or an oversized shove that folds every worse hand. Even when you use different sizes on each street, work backward from the river to see how much each bet will leave behind.
Rule of thumb: The math tells you how to get the stack in. The board and both players' possible hands tell you whether you should.
Practice backward from the river
Start with the 10bb pot and 30bb stack from the example. Guess the repeated size. Then check that an 8.2bb bet leaves 21.8bb and creates a 26.4bb river pot after a call. Next, make the river complete a flush and ask whether your overpair still wants to shove 21.8bb. The first pass trains the math. The second trains you to change the plan when a new card helps your opponent.
Keep studying
Apply the arithmetic to tiny-SPR 4-bet-pot planning, balance the final street with optimal bluff frequency for each bet size, and confirm that the value side begins with worse hands that can actually call the river.