Poker Bet Sizing Guide: GTO Bet Sizes by Street
Last updated: May 26, 2026
GTO bet sizing follows a clear progression by street: 25–33% pot on dry flops, 50–75% on turns, and 66–100% on polarized rivers. Sizing is not arbitrary — it must match your range. Small bets work across merged ranges; large bets apply pressure with polarized ranges. Random sizing, even with correct frequencies, creates exploitable patterns.
Why Bet Sizing Is More Important Than Bet Frequency
Most players focus on whether to bet — bet or check? — when the more impactful decision is how much to bet. Incorrect sizing leaks EV even when your frequency is correct. A value hand bet at 25% when 75% was optimal loses significant value per street. A bluff at 100% when 33% was correct pays off an opponent's call with bad odds on your end.
The fundamental principle: each bet size constructs a specific range. When you bet 25% on a dry flop, GTO assigns the entire range to that bet — value, bluffs, and medium hands all included. When you bet 75%, the range contracts to only strong value and pure bluffs. Mixing these sizes randomly dismantles the range construction and creates hands in your range that are severely over- or under-represented.
Practical takeaway: decide on 2 flop sizes (small and large), 1–2 turn sizes, and 1–2 river sizes. Use them consistently. Over thousands of hands, consistent sizing outperforms "optimal" random sizing by a significant margin simply because your ranges become unreadable and unexploitable.
GTO Bet Sizes by Street and Board Type
This table summarizes GTO-recommended bet sizes across all three post-flop streets. Use it as a reference guide for both live and online play.
Flop Bet Sizing — Small vs Large and When to Use Each
The flop is where sizing decisions are most consequential because they shape the entire hand's range construction. GTO identifies two primary flop sizing strategies: small (25–33% pot) and large (50–75% pot). Using both in the right spots covers nearly every GTO situation.
Small Flop Bet (25–33%)
Use on dry, static boards where draws are minimal. Bet with entire range — value, draws, and medium hands. The small size extracts thin value while risking minimal chips with weaker holdings.
Best on: A-7-2 rainbow, K-5-2 rainbow, unpaired high-card dry boards. The entire range bets one-third pot with high efficiency.
Large Flop Bet (50–75%)
Use on wet, connected boards with many draw possibilities. The large bet charges draws the maximum price and builds a larger pot with strong made hands.
Best on: J-T-9 two-tone, K-Q-J suited, 8-7-6 connected. The large size appropriately separates value from draws and denies equity.
Turn Bet Sizing — When to Go Bigger
Turn sizing should typically be larger than flop sizing. The reasoning: turn ranges are stronger and more polarized. After a flop bet and call, both ranges have narrowed — the caller likely has a real hand or draw, not pure air. This justifies a larger bet to extract maximum value and correctly charge draws at the higher pot size.
Standard turn sizing: 50–67% pot for most spots. Move to 75–100% pot when the turn card significantly improves your range (action card, overcard that helps you) or when stacks are getting short relative to the pot. Use overbets (120–150%) only when your range massively dominates — this is a high-variance line that requires confident range advantage.
One important note: do not automatically bet large on the turn because you bet large on the flop. Sizing should respond to the specific turn card, not just continue the flop's pattern. A blank turn after a 75% flop c-bet can often be 50% pot — the ranges have not shifted dramatically.
River Bet Sizing — The Polarized vs Merged Decision
River sizing is the most binary sizing decision in poker. On the river, you either have a polarized range (nuts + bluffs, no medium hands) or a merged range (thin value hands included). The correct sizing depends entirely on which type you have.
Polarized River Range → Large Bet (75–100%+ pot)
When your range consists of nutted hands and bluffs, use large sizing. Opponents must make a difficult binary decision (call with marginal hands or fold). Large bets maximize value from strong hands and apply maximum pressure on bluffs.
Merged River Range → Small Bet (33–50% pot)
When your range includes medium-strength thin value hands, use small sizing. These hands want calls from weaker medium-strength hands. A large bet would fold out all the hands you want to extract thin value from, while a small bet gets called by a wider range.
Overbet River (150–200% pot)
Reserve for spots where you have the absolute nuts or near-nuts and the opponent cannot have many strong hands. Requires both range advantage and the right board texture. Effective on monotone boards or when the 'nuts' category in your range is disproportionately large.
Two-Size Game Plan — Simplifying Without Sacrificing Too Much EV
GTO solvers use many sizes, but real poker — especially live — benefits from simplification. Research shows that using just two flop sizes (one small, one large) captures approximately 90–95% of the EV achievable with unlimited sizing options.
Practical framework: pick 33% and 67% as your two flop sizes. Use 33% on dry boards and 67% on wet boards. On the turn, use a single size (60–67%) for most spots, with an overbet option for specific range-dominating turns. On the river, use one sizing per range type: 75% for polarized, 40% for merged.
This two-size structure is easy to execute under pressure, is consistent enough to prevent opponents from reading patterns, and covers the vast majority of GTO-optimal situations. Master this system before adding a third size — the complexity cost exceeds the EV benefit for most players below the highest stakes.
Definitions
Frequently Asked Questions
What is the correct bet size in poker?
It depends on the street, board texture, and hand strength. As a baseline: 25–33% pot on dry flops, 50–75% on wet flops, 50–75% on turns, and 66–100% on rivers with polarized ranges. The most important principle: use consistent sizing per street so your bet size does not reveal your hand strength.
Should I always use the same bet size?
No — but picking 2–3 sizes per street and applying them correctly is significantly better than random sizing. Using one small size (25–33%) and one large size (60–75%) on the flop covers 90%+ of GTO situations. Adding a third size beyond that yields minimal gain and adds complexity. Consistency within a sizing system is more important than perfection.
What does 'pot-size bet' mean?
A bet equal to the total pot size before your bet. For example, if the pot is $100, a pot-size bet is $100. This gives the opponent 2:1 pot odds (they must call $100 to win $200 total) and requires exactly 33% equity to be a profitable call. Pot-size bets are typically used with polarized ranges on the river.
When should I overbet the pot?
Overbets (120%+ pot) are correct on turns and rivers when your range massively dominates your opponent's. This requires a range advantage — you have many more strong hands than they can have in that spot. Common overbet spots: A on A-K boards (aggressor has many more AA combos), nuts on specific monotone boards, or paired boards where your full house range far exceeds theirs.
Why do GTO solvers use small bets on some boards?
Small bets (25–33%) on dry boards allow the aggressor to bet with an entire range — including weak top pair and medium-strength hands — for thin value. Because the board is dry and the range is wide, a small bet extracts value across many hands simultaneously. On wet boards, a small bet does not adequately charge draws, so larger sizing is required.
How does position affect bet sizing?
In position (IP), players can often use smaller sizes because they have an informational advantage — acting last gives them more information. Out of position (OOP), larger sizes are sometimes needed to compensate for position disadvantage and to deny free cards effectively. This is why OOP triple-barrel lines frequently use larger sizings than equivalent IP lines.
What is a merged vs polarized betting range?
A polarized range contains only very strong hands (nuts) and bluffs — nothing in the middle. Large bets (75%+) are typically polarized. A merged range includes thin value hands (middle-strength hands like second pair, weak top pair) along with stronger hands. Small bets (25–50%) are typically merged. River sizing should match your range type: polarized range = large bet; merged range = small bet.
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