Why Open 2bb from UTG but 3bb from SB?

Why Opening Size Matters

"Isn't the raise size always just 3bb?" — No, it isn't.

Getting the size wrong leads to problems:

• Too large: High fold equity, but expensive bluffs; if called, you're stuck in a big pot OOP
• Too small: Cheap, but attracts too many callers — multiway pots crush top pair value

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Optimal Sizing by Position

Online (6-Max)

Position	Size	Reason
UTG	2–2.2bb	Highest chance of facing a 3-bet → minimize risk
HJ	2–2.3bb	Similar to UTG
CO	2.3–2.5bb	Only BTN/blinds left — can size up slightly
BTN	2.5bb	Only blinds to act → secure fold equity
SB	3bb	Compensate for OOP disadvantage → largest size

Live

Position	Size	Reason
All positions	3–4bb	A 2bb open in live games attracts too many callers
With limpers	+1bb per limper	2 limpers → raise to 5–6bb

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Why Smaller in EP and Larger in LP?

EP (UTG, HJ) — why use a smaller size:

• Many players left to act → higher 3-bet probability
• Low bluff frequency in opens → small risk is sufficient
• If 3-bet, you can fold → minimize losses

LP (BTN, SB) — why use a larger size:

• Only the blinds remain → lower 3-bet probability
• Opening with a wide range → need a bigger size to take down the pot
• SB is OOP, so the largest size aims to end the hand preflop

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Key Takeaways

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Source: GTO Wizard Blog, Upswing Poker, PokerCoaching