Heads-Up Preflop Strategy: Ranges for 1v1

Heads-up preflop strategy is preflop poker stripped to its skeleton: two players, two blinds, and constant pressure. With no one left to act behind you, the fear of running into a premium disappears, and both seats play far more hands than they ever would at a full table. The button (who posts the small blind and acts first preflop) opens a huge range, and the big blind defends nearly as wide. Master these two ranges and the 1v1 dynamic that drives them, and you’ve mastered the most range-intensive spot in poker.

The two-seat structure

Heads-up has only two positions, and they belong to the same two players every hand:

• Button / small blind (SB): posts the small blind, acts first preflop but last on every postflop street. This positional advantage postflop is why the button opens so wide.
• Big blind (BB): posts the big blind, acts last preflop (closing the action) but first postflop.

Because there are only two blinds to fight over and no third player to wake up with aces, both ranges balloon compared to full-table opening ranges. This is the extreme end of the same logic that governs blind-vs-blind play at a full table.

Button (SB) opening range

At 100bb, the button raises first-in with about 80-90% of hands. You’re folding only genuine garbage.

Category	Included heads-up?
All pairs (2-2 to A-A)	Yes
All suited hands	Yes
All suited-connected and one-gappers	Yes
Offsuit aces (A-2o+)	Yes
Offsuit kings and queens (K-2o+, Q-5o+)	Mostly yes
Offsuit trash (7-2o, 8-2o, 9-3o, J-2o)	Fold

The hands you actually fold from the button number only around 200 combos out of 1,326 — the worst disconnected offsuit holdings. Everything with a pair, a suit, or an ace-high blocker gets raised.

Big blind defending range

Facing that near-any-two open, the big blind is getting a wonderful price to continue and closes the action, so defense is very wide — commonly 70%+ of hands, split between calling and 3-betting.

• Flat-call: the bulk of your defends — medium and small suited hands, offsuit broadways, small pairs. You have position postflop… except you don’t, because the button acts last. So you call to see a flop cheaply and outplay a capped range.
• 3-bet (polarized): premiums (T-T+, A-Q+) for value, plus suited-blocker bluffs (suited wheel aces, suited kings) to punish the loose open and deny the button its positional edge.
• Fold: only the very worst offsuit hands the button also raises trash-wide with — and even many of those are profitable defends.

The math: why defense is so wide

Suppose the button opens to 2.5bb. The pot is now 2.5 (button) + 1 (your posted BB) = 3.5bb, and it costs you 1.5bb more to call. Your pot odds are 1.5 / (3.5 + 1.5) = 30%. You only need about 30% equity against the button’s opening range to make a call break even. Against an 85% opening range, even a hand like Q♦ 4♦ clears that bar comfortably — it has around 40% equity heads-up. That’s why folding hands with any suit or connectedness from the big blind is such a costly mistake: the price is simply too good.

A worked heads-up spot

You’re on the button with K♣ 6♣ at 100bb.

• This is a clear open. K-6 suited has a king blocker, flush potential, and dominates a big chunk of the big blind’s calling range. You raise to 2.5bb.
• The big blind calls (as they will with most hands). You flop bottom pair, a flush draw, or overcards often enough to keep applying pressure, and you act last postflop — the button’s structural edge.

Now flip seats. You’re in the big blind with that same K♣ 6♣ facing a button open.

• Flat-calling is fine — you’re closing the action at a 30% price with a hand that flops plenty of equity.
• Against a very aggressive button, you can also mix in a 3-bet, since K-6 suited blocks some of the button’s strong kings and can barrel when called.

Short-stack heads-up: push-or-fold

Everything above assumes a deep 100bb stack. As stacks shrink — common at the end of a heads-up SNG or tournament — min-raising gives way to open-shoving. Around 15 big blinds and below, the button’s best play with many hands is to move all-in, and the big blind calls off with a wide but disciplined range. The ranges tighten as stacks drop because there’s no postflop play left to win the pot — it’s all preflop equity. Getting the risk-reward math right here overlaps heavily with pot and equity math.

Common heads-up mistakes

• Playing full-ring ranges. Folding hands like Q-4 suited from the big blind hands the button free blinds every orbit.
• Never 3-betting the big blind. A pure flat-call defense lets the button realize its position uncontested. Mix in polarized 3-bets.
• Limping the button. With such a strong positional edge, raising first-in beats limping in almost every spot at 100bb.
• Not adjusting for stack depth. A 100bb strategy applied at 12bb ignores the push-or-fold reality.

Putting it together

Heads-up preflop is a two-seat blind war: the button opens 80-90% of hands, the big blind defends 70%+ at a 30% price, and short stacks collapse into push-or-fold. Widen everything, defend your blind aggressively, and adjust your ranges as the stack shrinks. Build from the same principles as full-table opening ranges, then compress them into two seats. The complete preflop framework lives in the preflop strategy hub.