66 vs 55 Odds: Pocket Sixes vs Pocket Fives
Last updated: May 27, 2026
Pocket Sixes (66) wins 81.5% of the time against Pocket Fives (55) preflop. 55 wins 16.8% with ties at 1.7%. This one-rank-gap matchup is the most complex in the 66 domination range. Unlike wider-gap matchups where the lower pair is a pure set-mine, 55 has a wheel board advantage (access to A-2-3-4-5 straight boards) and both hands interact with the same low-mid board zone — creating shared OESD scenarios that don't exist when the pairs are further apart. 55's 16.8% equity is the highest of any lower pair vs 66, reflecting this elevated secondary equity.
The Exact Number: 81.5% vs 16.8%
66's 64.7-point advantage over 55 is the smallest margin in 66's domination range, reflecting 55's relatively higher board connectivity. The 1.7% tie rate is consistent with other low-pair matchups. 55's 16.8% equity is higher than 44's equity (16.6%) against 66 and nearly a full point higher than 22's equity (16.0%) against 66 — a measurable difference driven by 55's wheel draw access and shared board zone with 66.
66 Wins
81.5%
55 Wins
16.8%
Tie
1.7%
55's 16.8% equity breaks down as: approximately 10.4% from set-out probability (11.8% × 88.5%), approximately 2.5% from wheel board and low straight draw scenarios (A-2-3, 2-3-4, 4-5-6 boards), approximately 0.8% from runner-runner quads or boats, and approximately 3.1% from board-play ties and miscellaneous runouts.
Does the Suit Matter?
Suit combinations affect 66 vs 55 by approximately 0.4 percentage points. Since 55's primary equity driver (set outs) is completely suit-independent, the small suit variation comes from flush draw possibilities when 55 shares a suit with a six. In one-rank-gap matchups, flush draw equity is marginally more relevant than in wider-gap matchups because connected boards allow the lower pair to pick up both straight and flush draw combinations simultaneously.
Preflop equity by suit combination
Post-Flop: When 55 Is Most Dangerous to 66
Post-flop in 66 vs 55, the board texture is even more critical than in wider-gap matchups. A five on the flop reverses the matchup; a six on the flop ends it for 55; and the 4-5-6 board is 55's strongest secondary equity scenario — flopping a set on a board where both straight draws point inward. The 5-6-x set-over-set cooler is more frequent here than in non-adjacent pair matchups.
Equity given specific flops and runouts
Why One-Rank Gap Changes Everything: 66 vs 55 Complexity
Compare 66 vs 55 to 66 vs 33: against 33, the lower pair has essentially no secondary equity because three-high boards are rare and fives don't share board combinations with sixes. Against 55, the situation is fundamentally different. Both 55 and 66 live in the 3-8 board zone:
On 3-4-5 boards, 55 has a set and 66 has an overpair on a connected board. On 4-5-6 boards, 55 has a middle set and the board has multiple straight draw possibilities for anyone holding 3-7 or 7-8. On 5-6-7 boards, 66 has a set and 55 is drawing thin — but note that 5-6-7 creates a set for 66 while 55 now has a gutshot (needing an 8 for 5-6-7-8-9 or a 4 for 4-5-6-7-8). These intersecting board interactions produce a more nuanced post-flop game than any wider-gap domination matchup in the low-pair zone.
55 equity sources vs 66
- Flop a set of fives (11.8%) × win from there (88.5%)~10.4%
- Wheel draw + low OESD boards (A-2-3, 2-3-4, 4-5-6)~2.5%
- Runner-runner quads or boats~0.8%
- Board-play ties and miscellaneous runouts~3.1%
- Total 55 equity16.8%
66-Range Pair Matchup Reference Table
66's equity against every lower pocket pair. Note how 55's higher equity (16.8%) vs wider-gap opponents reflects the one-rank-gap connectivity effect. All figures are baseline (no suit overlap).
Key pattern: the bottom rows show that one-rank-gap matchups (66 vs 55, 77 vs 66, TT vs 99) all cluster around 81.5% for the favourite — the tightest point in the domination spectrum. As the gap widens, the favourite's equity rises incrementally (66 vs 22 reaches 82.0%). The final entry (33 vs 22 at 83.0%) shows that very-low pair matchups have higher favourite equity because both pairs share so few board combinations that secondary equity is essentially zero.
Definitions
Frequently Asked Questions
What are the exact 66 vs 55 preflop odds?
Pocket Sixes (66) win 81.5% of the time against Pocket Fives (55) preflop. 55 wins 16.8% and ties account for 1.7%. This is the tightest-gap matchup in the 66 range and involves unique complexity: 55 has a wheel board advantage (access to A-2-3-4-5 straight boards that 66 is less connected to) and both pairs interact with overlapping sets of straight draw boards. The 16.8% for 55 is higher than 44's equity (16.6%) or 33's (16.4%) against 66, reflecting 55's slightly higher board connectivity relative to 66.
What is the wheel board advantage that 55 has over 66?
The 'wheel' is the A-2-3-4-5 straight — the lowest possible straight in poker. 55 participates in the wheel draw in a way that 66 cannot fully replicate: on boards like A-2-3 or A-2-4 or A-3-4, 55 can catch a three and four (for A-2-3-4-5) or similar combinations to complete a wheel. 66 requires a 2-3-4-5 combination for its own low straight (giving 66 a straight from 2-6), which is a different draw requiring different board cards. The practical effect: on very low boards (A-2-3, 2-3-4, A-3-4), 55 has slightly better secondary equity than 66 because fives connect more naturally to wheel draws than sixes do. This is a subtle but measurable edge that contributes to 55's 16.8% equity being higher than 44's 16.6% against 66.
What makes 4-5-6 one of 55's strongest boards against 66?
A 4-5-6 board gives 55 the middle set of fives — a very strong holding — combined with both open-ended straight draw potential from both sides of the board. A 3 completes 3-4-5-6-7 doesn't directly; but a 7 gives 3-4-5-6-7... wait — 4-5-6 with a 7 gives 55 a straight (4-5-6-7-8 needs an 8), or a 3 gives 3-4-5-6-7 to any player. More precisely: 55 on 4-5-6 has a set and the board is part of multiple straight draws (3-4-5-6-7 and 4-5-6-7-8). This board compresses 66's equity significantly: 66 has top set on 4-5-6 — wait, 66 has an overpair (top pair is six) on 4-5-6. 55 has middle set. 66's top set would only occur on a 6-x-x board. On 4-5-6 specifically, 66 has only an overpair, not a set. This dramatically shifts equity: 55 has middle set (~88.5% favourite if 66 has just an overpair), making the 4-5-6 board one of 55's best scenarios.
What is the 5-6-x set-over-set scenario?
On 5-6-x flops, both 66 and 55 have flopped three-of-a-kind simultaneously — the classic one-rank-gap cooler. 66 has top set (three sixes) and 55 has bottom set (three fives). 66 wins approximately 85% from this point. The only path for 55 to win is making quad fives or running out a full house of fives-over-sixes that beats 66's full house of sixes-over-fives. Because the gap between the pairs is only one rank, the 5-6-x set-over-set is somewhat more frequent than wider-gap set-over-set scenarios — five and six boards both appear regularly in Texas Hold'em, increasing the relative probability of this cooler.
Why does 66 vs 55 have more shared board complexity than wider-gap matchups?
One-rank-gap matchups (66 vs 55, 77 vs 66, 88 vs 77) have uniquely elevated board complexity because both pairs exist in the same narrow zone of the card spectrum. On boards like 3-4-5, 4-5-6, 5-6-7, or 6-7-8, both hands interact: 55 might have middle set, 66 might have an overpair, or both might be drawing to straights. In wider-gap matchups (66 vs 33), the lower pair has almost no secondary equity because threes and sixes rarely share boards. In 66 vs 55, the adjacent nature of the pairs means both hands can simultaneously be threatened by or benefit from boards in the 3-8 range. This shared board zone is why the tie rate (1.7%) and post-flop complexity are elevated vs the baseline for wider-gap matchups.
Can the tie rate be elevated in 66 vs 55 compared to wider-gap matchups?
The tie rate is 1.7% for 66 vs 55, consistent with other low-pair matchups. However, the underlying mechanics differ: in wide-gap matchups (66 vs 33), ties almost exclusively come from five-card board straights being played by both players. In 66 vs 55, ties can also arise from more complex board situations where both pairs contribute to the same five-card board combination. The 1.7% figure is the net result of these slightly different tie path mechanics — the rate is stable but the composition of ties is somewhat more varied in the one-rank-gap matchup.
How does 66 vs 55 fit into the full pair-vs-pair equity spectrum?
66 vs 55 (81.5%) is at the bottom of 66's domination range — the same equity as 77 vs 66 (81.5%), reflecting the structural parallel between one-rank-gap medium-low pair matchups. The full 66 reference: 66 vs 55 (81.5%), 66 vs 44 (81.7%), 66 vs 33 (81.9%), 66 vs 22 (82.0%). All fall within a tight 0.5-point band. Compared to the TT vs 99 matchup (also 81.5%), the equity figures are nearly identical — demonstrating that the set-out mechanism produces remarkably consistent equity across all pair domination matchups regardless of absolute pair rank.
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