--- title: "ATo vs 55: preflop equity" url: "https://georgelipoker.com/equity/ato-vs-55.md" canonical_url: "https://georgelipoker.com/equity/ato-vs-55" last_updated: "2026-10-23" type: "reference" summary: "Who is ahead, ATo or 55? 55 leads 53.46% to 46.54% before the flop, counted exactly over every board, with the split by flop type and suit." related: ["https://georgelipoker.com/equity/ato-vs-qjs.md", "https://georgelipoker.com/equity/ato-vs-k9s.md", "https://georgelipoker.com/equity/kjs-vs-55.md"] --- # ATo vs 55: preflop equity Who is ahead, ATo or 55? 55 leads 53.46% to 46.54% before the flop, counted exactly over every board, with the split by flop type and suit. Averaged over every possible board, 55 is ahead of ATo by 6.92 points of equity, 53.46% to 46.54%. ## ATo against 55: the numbers **Exact preflop results for ATo against 55, in percent** | Hand | Wins | Ties | Loses | Equity | | --- | --- | --- | --- | --- | | ATo | 46.314 | 0.444 | 53.242 | 46.536 | | 55 | 53.242 | 0.444 | 46.314 | 53.464 | ATo and 55 are an offsuit hand and a pocket pair, in that order. One hand holds a pair and the other holds two cards that both outrank it, which keeps the equity closer than most people expect. That is a slim edge: neither hand is far ahead. Ties are 0.44% of the outcomes here; each tied board gives both hands half the pot. The hand ranking puts ATo at 19 and 55 at 27 out of 169 starting hands. **Boards behind the percentages: 123,285,888 counted in all** | Hand | Boards won, about | Boards tied, about | Boards lost, about | | --- | --- | --- | --- | | ATo | 57,099,000 | 547,000 | 65,640,000 | | 55 | 65,640,000 | 547,000 | 57,099,000 | 72 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. **ATo 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) | | --- | --- | --- | --- | --- | | ATo | 0.870 | 2.159 | 1.878 | 1.149 | | 55 | 1.149 | 1.878 | 2.159 | 0.870 | In the last column, a pot-to-call ratio at or above the figure makes a call break even or better at this equity. ## Who is ahead on which flops Split by what the flop looks like, 55 peaks at 78.22% on low rainbow flops (nine high or lower) and bottoms out at 46.83% on rainbow flops topped by a ten or better. The overall edge for 55 hides rainbow flops topped by a ten or better, where ATo comes out in front. **ATo against 55 by flop texture, in percent** | Flop | Share of flops | ATo wins | Ties | 55 wins | ATo equity | | --- | --- | --- | --- | --- | --- | | Rainbow, ten or higher | 24.717 | 53.054 | 0.242 | 46.704 | 53.175 | | Rainbow, nine or lower | 6.314 | 21.419 | 0.719 | 77.862 | 21.778 | | Two-tone | 46.485 | 46.926 | 0.326 | 52.748 | 47.089 | | Monotone | 5.151 | 48.566 | 1.844 | 49.590 | 49.488 | | Paired | 17.333 | 43.464 | 0.532 | 56.004 | 43.730 | Read the flop types this way: rainbow has three suits, two-tone has two cards of one suit, monotone has three, and paired repeats a rank. ## Compared with a random hand A random hand would give ATo 62.72% and 55 60.33%. Against each other the change is -16.18 points for ATo and -6.87 for 55. **ATo 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 | | --- | --- | --- | --- | --- | | ATo, all flops | 46.536 | 62.722 | -16.186 | 0.74194 | | ATo, rainbow, ten or higher | 53.175 | 62.722 | -9.547 | 0.84779 | | ATo, rainbow, nine or lower | 21.778 | 62.722 | -40.944 | 0.34721 | | ATo, two-tone | 47.089 | 62.722 | -15.633 | 0.75076 | | ATo, monotone | 49.488 | 62.722 | -13.234 | 0.78901 | | ATo, paired | 43.730 | 62.722 | -18.992 | 0.69720 | | 55, all flops | 53.464 | 60.325 | -6.861 | 0.88627 | | 55, rainbow, ten or higher | 46.825 | 60.325 | -13.500 | 0.77621 | | 55, rainbow, nine or lower | 78.222 | 60.325 | +17.897 | 1.29668 | | 55, two-tone | 52.911 | 60.325 | -7.414 | 0.87710 | | 55, monotone | 50.512 | 60.325 | -9.813 | 0.83733 | | 55, paired | 56.270 | 60.325 | -4.055 | 0.93278 | ## Does a shared suit matter? When the hands share a suit, 55 holds 53.38%; when they do not, it holds 53.88%. 55 does better with no shared suit, by 0.50 points. **ATo against 55 by suit overlap, in percent** | Deals | Specific deals | Share of deals | ATo wins | Ties | 55 wins | ATo equity | | --- | --- | --- | --- | --- | --- | --- | | Share a suit | 60 | 83.33 | 46.390 | 0.459 | 53.151 | 46.620 | | No shared suit | 12 | 16.67 | 45.936 | 0.370 | 53.694 | 46.121 | ## How often this matchup comes up ATo against 55 is made up of 72 specific-card matchups in one seat order, 0.0044% of the 1,624,350 ordered deals, and 144 counting both seat orders, 0.0089%. ## A worked example Take a $200 pot built from $100 each. 55's equity of 53.46% is worth $106.92, a $6.92 edge, and ATo's 46.54% is worth $93.08, which is $6.92 under its stake. Think in thousands: about 532 of 1,000 go to 55, about 463 go to ATo, and about 5 are chopped. ## The same matchup from the other side Read it from the other side: 55 against ATo is the same matchup with the numbers swapped, so 55 holds 53.46% and ATo holds 46.54%. That address sends you back to this page. ## Keep exploring Open the calculator with AsTh against 5d5c already entered, a deal with no shared suit, and change any card to try your own hand. The matchups after it each swap one hand for a nearby one in the ranking. - [Open AsTh against 5d5c in the equity calculator](https://georgelipoker.com/tools/equity-calculator.md#p1=AsTh&p2=5d5c) - [ATo combos](https://georgelipoker.com/combos/ato.md) - [55 combos](https://georgelipoker.com/combos/55.md) - [ATo vs QJs](https://georgelipoker.com/equity/ato-vs-qjs.md) - [ATo vs K9s](https://georgelipoker.com/equity/ato-vs-k9s.md) - [KJs vs 55](https://georgelipoker.com/equity/kjs-vs-55.md) - [All hand matchups](https://georgelipoker.com/equity.md) ## How this was computed The page is built from a full enumeration: 1,712,304 boards, every suit pattern of the 72 specific deals, both seven-card hands evaluated. A tie is worth half a win to each hand, and a board is tallied under each of its ten possible flops for the texture rows. Source: our own exact count from the GeorgeLiPoker poker math library. No outside data is used. ## Related - [ATo vs QJs: preflop equity](https://georgelipoker.com/equity/ato-vs-qjs.md) - [ATo vs K9s: preflop equity](https://georgelipoker.com/equity/ato-vs-k9s.md) - [KJs vs 55: preflop equity](https://georgelipoker.com/equity/kjs-vs-55.md)