What Is a 3bet: Definition, Timing, and Range

In modern poker, if your only preflop actions are raise and fold, your profit ceiling is essentially fixed. The 3bet opens up a second dimension of attack: actively building the pot, pinning the opponent's range in an awkward spot, and creating value for your bluffs. This article systematically covers the definition and three core purposes of the 3bet, the sizing differences between IP and OOP, the principles behind value and bluff range design, and a framework for facing a 4bet — these are foundations you must master to win consistently at NL50 and above.

What Is a 3bet

A 3bet is a re-raise after an open-raise preflop. The name comes from the count of bets:

• Big blind = 1st bet
• Open-raise = 2nd bet
• Re-raise = 3rd bet (3bet)
• Re-re-raise = 4th bet (4bet)
• Re-re-re-raise = 5th bet (5bet, usually all-in)

How a 3bet differs from a limp and a flat call:

• limp: just call the 1 BB without raising
• flat call: just call your opponent's open-raise
• 3bet: don't call — re-raise instead

When you face an open from the BB, your "1st bet" is already a forced bet, so a re-raise from the BB is technically also a 3bet.

The Three Purposes of a 3bet

Value 3bet

Use a strong hand (QQ+, AK) to build the pot, expecting your opponent to flat call with a middle pair or broadway, then extract value postflop with the stronger holding. The return on this kind of 3bet comes from "opponent's mistakes after they call."

Bluff 3bet

Use marginal hands with blocker effects (A5s, K9s, A3s), aiming for one of:

1. Opponent folds preflop (the ideal outcome)
2. Opponent calls but struggles postflop because of low SPR
3. Apply more pressure postflop with a continuation bet

The +EV source of a bluff 3bet is not "winning at showdown" but "opponent folds a better hand preflop or on the flop."

Squeeze 3bet

When someone opens and at least one player flat-calls, your 3bet is called a squeeze. The size is typically larger (normal 3bet + 1× per caller), and the pressure on the caller is especially effective — callers rarely flat first with a range strong enough to call a 3bet.

3bet Sizing

IP vs OOP is the primary determinant of sizing:

• IP 3bet: 3× the open (e.g. 3bb open → 9bb 3bet)
• OOP 3bet: 4× the open (e.g. 3bb open → 12bb 3bet)

Why OOP needs a larger size: positional disadvantage makes you play worse postflop, so you want to discourage opponents from calling preflop. A larger size raises the equity threshold opponents need to continue, narrowing the postflop range you have to defend out of position.

Short-stack adjustment: with shallower stacks (e.g. 50bb), 3bet sizes scale up relatively — you want to worsen your opponent's implied odds. With deep stacks (200bb+) you can size slightly smaller, but never below 2.5×.

Designing the 3bet Range

A good 3bet range is polarized: top-end value at one pole, blocker-laden marginal hands at the other. Avoid the middle that flatting covers.

Example: BTN vs CO open

Value (~50% of the 3bet range):

• QQ+
• AK (AKs + AKo)
• Occasional JJ / AQs

Bluff (~50% of the 3bet range):

• Suited Ax blockers: A5s, A4s, A3s
• Suited Kx blockers: K8s, K9s
• Weak suited connectors: T8s, 76s (rarely)

Total 3bet frequency: about 10-12%.

Why This Composition

• Value has raw strength — no fear of a 4bet shove (QQ+ AK is still +EV against a 5bet range)
• Bluffs have blocker effects: A5s blocks the As in the opponent's AA/AQ/AK, shrinking their 4bet range and making the overall pressure more effective
• The middle (e.g. JTs, 99, KJs) is better as a flat call — strong postflop playability, but awkward to play if 3bet and then 4bet

When to 3bet

By Opponent's Position

• vs EP open: mostly value (QQ+ AK), light blocker bluffs
• vs MP/LP open: widen the 3bet range, increase the bluff ratio
• vs blind open: blind opens are often slightly tight (or extremely wide) — adjust based on observation

By Opponent's Tendencies

• tight-passive opponents: bluff 3bets are highly effective (high fold rate) — expand the bluff range
• loose-aggressive opponents: bluff 3bets are inefficient (they 4bet readily) — tighten bluffs to strong value only
• passive callers: lean toward pure value (they won't fold preflop, but they will call and then fold to a cbet)

By Your Own Position

• BTN: the best 3bet position — high preflop fold rate, always IP postflop
• CO: second-best, but BTN still acts behind you — watch for cold 4bets after your 3bet
• SB/BB: prefer 3bet or fold over flatting (being OOP postflop crushes the EV of flatting)

What to Do When 4bet

When your 3bet gets 4bet, you have three options: 5bet shove / call / fold.

5bet Shove Range

Typically QQ+ and AK. More precisely:

• Value: KK+ (occasionally QQ)
• Pure bluff shove: hands like A5s — pure blocker + 0 equity-when-called (rare, requires the opponent to 4bet wide)

Calling the 4bet

• Usually very narrow — in most cases the SPR of a 4bet pot is low (3-5), leaving little postflop room to maneuver
• JJ and AQs are typical "marginal call" candidates; the decision depends on stack depth and the opponent's 4bet range

Folding to a 4bet

All bluff 3bets (A5s, K9s, etc.) basically have to fold to a 4bet. Their EV source is "opponent folds preflop" — when the opponent raises instead, that EV disappears.

A simple range-balance principle: the 5bet shove range should be 2:1 value-to-bluff, so opponents can't 4bet you mindlessly.

Common Mistakes

Mistake 1: 3betting only AA/KK. The range is too narrow — opponents can easily fold to your 3bet and give you the pot, but long-term you become exploitable.

Mistake 2: Using the same 3bet range regardless of position. Playing a BTN range from UTG bleeds chips to the players behind you.

Mistake 3: Bluff-3betting with trash hands. 72o is not a 3bet bluff candidate — no blocker effect, complete air postflop. Selecting blockers is the core of constructing a bluff 3bet range.

Mistake 4: Always cbetting after a 3bet. A preflop 3bet doesn't imply an automatic flop cbet. On certain board textures (e.g. ones that favor the opponent's range), checking is the better choice. See when to use a continuation bet.

Mistake 5: Judging 3bet quality by results. A bluff 3bet that gets called and loses on the flop doesn't mean the 3bet itself was -EV. Over the long run, each bluff 3bet contributes stable expected value — a single result tells you nothing.

Summary

The 3bet is the key transition from amateur to serious play in modern poker. To master it:

1. Understand the three purposes of the 3bet: value / bluff / squeeze, each with its own range design
2. Adjust sizing by position: 3× IP, 4× OOP, larger when stacks are short
3. Build a polarized range: pure value + pure blocker bluffs, skip the middle (flat instead)
4. Stay disciplined against a 4bet: most bluff 3bets must fold; the 5bet range needs a value:bluff balance

In practice, 3bet strength and range thinking are mutually dependent — a 3bet without range thinking is just chaos, while a 3bet grounded in range thinking is a stable +EV weapon.