What legal means in practice
If the pot is 12 and villain bets 4, the largest legal raise is to 20 total. You are not guessing at a "big enough" size. You are using the exact pot after the call, then deciding whether that cap serves your range.
Pot limit geometry
Pot-limit bet geometry that plans the next street, not just the current raise.
In pot-limit, the best size is the one that creates the right future stack geometry. The ceiling is legal, but the real question is whether the raise leaves the correct turn SPR, forces the opponent into a condensed continue range, and opens a river line you can actually use.
Legal raise sizing
Count the pot, not your intuition.
The legal ceiling in pot-limit is mechanical. When a bet goes in, the maximum raise is built from the pot after you match that bet. If you do not count the pot correctly, every future street is distorted.
Geometry starts with the stack left behind
The raise size matters because it changes the remaining stack. A good pot-limit size leaves a turn or river configuration you can continue on, rather than trapping your range in a high-SPR spot with no leverage.
Preflop
Use pot-limit opens and 3-bets to keep the pot growth aligned with stack depth. The goal is not maximum chip intake; it is controlled leverage.
Flop
Flop sizing should decide whether the turn becomes a polar street or a control street. A raise that ignores turn geometry is usually too small or too large.
River
River sizing is strongest when the prior streets already capped the opponent and preserved your blocker/value split. The final bet should complete the earlier plan.
Sizing ladder
Choose the branch that matches the street, not the size you like.
Pot-limit gives you fewer degrees of freedom than no limit, which makes the decision tree cleaner if you treat each size as a geometry decision. The ladder is not a menu; it is a sequence of commitments.
Build the pot with position in mind
In deep pots, a larger open or 3-bet can be correct when it moves the hand toward a profitable SPR for your strong continue range. In shallower spots, the same size may overbuild the pot and weaken your post-flop edge.
Use a size that clarifies the turn
On boards where your range has nut advantage, a small bet can keep weaker continues in while still building toward a turn polar branch. On static boards, the cap often belongs to the caller because the raise does not buy enough fold equity.
Polarise when the range gap is real
The turn is where pot-limit hands often become easiest to misplay. If you can make the remaining stack awkward for the caller, the cap is worth using. If not, keep the pot smaller and preserve river maneuverability.
Worked examples
Three geometry problems, three different answers.
The right pot-limit size depends on whether the range wants to keep dominated hands in, force a narrow continue band, or arrive at a river where a value bet and a bluff can both represent the same story.
Single-raised pot, value-heavy flop
You open, get one caller, and see a board where your range has the strong top-end advantage. A small flop size works because it keeps worse continues in while preserving a turn SPR that still supports a polar second barrel.
Takeaway: do not over-pot the flop just because you can. If the turn is the real leverage street, the flop should set that street up instead of spending the whole stack too early.
Turn card that changes the continue band
The flop was checked or size-controlled, then a turn card arrives that improves your perceived nutted range. Now the cap is useful because it forces the opponent to defend only the strongest continues.
Takeaway: polar turns are for spots where the remaining range gap is large enough that a near-pot or pot-sized bet sharply divides value from bluff-catchers.
River after a deliberate turn build
You took a line that left a river stack behind with real pressure. The river is now a simple split between a value-heavy cap and a blocker bluff that removes the opponent's best continues.
Takeaway: the river is not where geometry starts. It is where the earlier sizing plan gets cashed in.
Compact drills
Two scenario cards to make the math automatic.
Run these spots until the count, the cap, and the next-street stack all feel like one calculation instead of three separate thoughts.
Count the cap
Input: pot size, villain bet, stack behind, and your intended line.
Task: compute the legal raise, then decide whether that size leaves a useful turn SPR or overcommits the hand class.
River setup audit
Input: flop size, turn size, and the board texture that arrives on the river.
Task: determine whether the river is now a value bet, blocker bluff, or check, and identify which previous street should have been larger or smaller.
Study links
Use the lesson with the tools.
These links keep the page connected to the existing NL Secrets pot-limit workflow instead of turning it into a dead-end article.