--- title: "66 vs 55: preflop equity" url: "https://georgelipoker.com/equity/66-vs-55.md" canonical_url: "https://georgelipoker.com/equity/66-vs-55" last_updated: "2026-10-23" type: "reference" summary: "66 is a big favorite over 55 before the flop: 81.36% to 18.64% equity, counted exactly over every board, with the split by flop type and suit." related: ["https://georgelipoker.com/equity/66-vs-qjs.md", "https://georgelipoker.com/equity/66-vs-k9s.md", "https://georgelipoker.com/equity/a9s-vs-55.md"] --- # 66 vs 55: preflop equity 66 is a big favorite over 55 before the flop: 81.36% to 18.64% equity, counted exactly over every board, with the split by flop type and suit. Before any board card is dealt, 66 holds 81.36% equity against 55, which leaves 55 with 18.64%. ## 66 against 55: the numbers **Exact preflop results for 66 against 55, in percent** | Hand | Wins | Ties | Loses | Equity | | --- | --- | --- | --- | --- | | 66 | 80.385 | 1.949 | 17.666 | 81.359 | | 55 | 17.666 | 1.949 | 80.385 | 18.641 | Here pocket pairs face each other, 66 on one side and 55 on the other. Two pairs against each other is a one-way street: the lower pair needs one of its two remaining cards. 66 is a big favorite here before anyone sees a flop. A split pot comes up on 1.95% of boards, so the wins and the equity differ by half of that. Place 17 of 169 belongs to 66 and place 27 belongs to 55 in the ranking against a random hand. **Boards behind the percentages: 61,642,944 counted in all** | Hand | Boards won, about | Boards tied, about | Boards lost, about | | --- | --- | --- | --- | | 66 | 49,552,000 | 1,201,000 | 10,890,000 | | 55 | 10,890,000 | 1,201,000 | 49,552,000 | 36 specific deals times 1,712,304 boards gives the exact total. The won, tied and lost counts are approximations from the five-decimal percentages, rounded to the nearest thousand. **66 against 55 read as odds** | Hand | Equity as odds (to 1) | Wins one deal in | Loses one deal in | Pot odds needed to call (to 1) | | --- | --- | --- | --- | --- | | 66 | 4.365 | 1.244 | 5.661 | 0.229 | | 55 | 0.229 | 5.661 | 1.244 | 4.365 | The last column is the break-even price: the pot odds a call needs to offer, as a ratio of pot to call. ## Who is ahead on which flops If you know the kind of flop that came, the numbers shift: 66 holds 84.39% on paired flops and 75.42% on low rainbow flops (nine high or lower). 66 stays ahead on all five textures. **66 against 55 by flop texture, in percent** | Flop | Share of flops | 66 wins | Ties | 55 wins | 66 equity | | --- | --- | --- | --- | --- | --- | | Rainbow, ten or higher | 25.844 | 81.989 | 1.170 | 16.841 | 82.574 | | Rainbow, nine or lower | 5.065 | 75.099 | 0.650 | 24.251 | 75.424 | | Two-tone | 46.363 | 80.249 | 1.069 | 18.682 | 80.783 | | Monotone | 5.152 | 74.620 | 2.681 | 22.699 | 75.961 | | Paired | 17.576 | 81.598 | 5.575 | 12.827 | 84.385 | A rainbow flop shows three suits, a two-tone flop repeats one suit, a monotone flop is a single suit, and a paired flop repeats a rank. ## Compared with a random hand How much does the opponent matter? Compared with its random-hand 63.29%, 66 changes by +18.07 points, and 55, from 60.33%, by -41.69. **66 and 55 here compared with each against a random hand, in percent** | Case | Equity here | Against a random hand | Change in points | Times the random-hand equity | | --- | --- | --- | --- | --- | | 66, all flops | 81.359 | 63.285 | +18.074 | 1.28560 | | 66, rainbow, ten or higher | 82.574 | 63.285 | +19.289 | 1.30480 | | 66, rainbow, nine or lower | 75.424 | 63.285 | +12.139 | 1.19181 | | 66, two-tone | 80.783 | 63.285 | +17.498 | 1.27650 | | 66, monotone | 75.961 | 63.285 | +12.676 | 1.20030 | | 66, paired | 84.385 | 63.285 | +21.100 | 1.33341 | | 55, all flops | 18.641 | 60.325 | -41.684 | 0.30901 | | 55, rainbow, ten or higher | 17.426 | 60.325 | -42.899 | 0.28887 | | 55, rainbow, nine or lower | 24.576 | 60.325 | -35.749 | 0.40739 | | 55, two-tone | 19.217 | 60.325 | -41.108 | 0.31856 | | 55, monotone | 24.039 | 60.325 | -36.286 | 0.39849 | | 55, paired | 15.615 | 60.325 | -44.710 | 0.25885 | ## Does a shared suit matter? Looking only at deals where the hands share a suit, 66 has 81.50%; looking only at deals where they do not, 80.67%. 66 does better with a shared suit, by 0.83 points. **66 against 55 by suit overlap, in percent** | Deals | Specific deals | Share of deals | 66 wins | Ties | 55 wins | 66 equity | | --- | --- | --- | --- | --- | --- | --- | | Share a suit | 30 | 83.33 | 80.515 | 1.963 | 17.522 | 81.497 | | No shared suit | 6 | 16.67 | 79.734 | 1.875 | 18.391 | 80.672 | ## How often this matchup comes up Counting specific cards, 66 against 55 appears in 36 of the 1,624,350 ordered heads-up deals (0.0022%), and in 72 when the seats are swapped too (0.0044%). ## A worked example With $100 from each side, the $200 pot is split on average as $162.72 for 66 and $37.28 for 55; the first side gains $62.72 per all-in and the second gives up $62.72. Over a long run, 1,000 deals split into about 804 for 66, 177 for 55 and 19 tied. ## The same matchup from the other side If you came looking for 55 against 66, the numbers are the same with the hands swapped: 18.64% and 81.36%. ## Keep exploring 6s6h against 5d5c is a ready-made deal for the calculator, with no suit in common between the hands. The neighboring matchups below replace one hand with another of similar strength. - [Open 6s6h against 5d5c in the equity calculator](https://georgelipoker.com/tools/equity-calculator.md#p1=6s6h&p2=5d5c) - [66 combos](https://georgelipoker.com/combos/66.md) - [55 combos](https://georgelipoker.com/combos/55.md) - [66 vs QJs](https://georgelipoker.com/equity/66-vs-qjs.md) - [66 vs K9s](https://georgelipoker.com/equity/66-vs-k9s.md) - [A9s vs 55](https://georgelipoker.com/equity/a9s-vs-55.md) - [All hand matchups](https://georgelipoker.com/equity.md) ## How this was computed Method: exact enumeration. The 36 specific deals are grouped by suit pattern, each is run against all 1,712,304 boards, and both seven-card hands are scored. Equity adds half of every tie, and flop textures are tallied over the ten flops inside each board. Source: our own exact count from the GeorgeLiPoker poker math library. No outside data is used. ## Related - [66 vs QJs: preflop equity](https://georgelipoker.com/equity/66-vs-qjs.md) - [66 vs K9s: preflop equity](https://georgelipoker.com/equity/66-vs-k9s.md) - [A9s vs 55: preflop equity](https://georgelipoker.com/equity/a9s-vs-55.md)