--- title: "A9s vs ATo: preflop equity" url: "https://georgelipoker.com/equity/a9s-vs-ato.md" canonical_url: "https://georgelipoker.com/equity/a9s-vs-ato" last_updated: "2026-10-23" type: "reference" summary: "ATo is a big favorite over A9s before the flop: 67.87% to 32.14% equity, counted exactly over every board, with the split by flop type and suit." related: ["https://georgelipoker.com/equity/a9s-vs-kjs.md", "https://georgelipoker.com/equity/a9s-vs-a8s.md", "https://georgelipoker.com/equity/66-vs-ato.md"] --- # A9s vs ATo: preflop equity ATo is a big favorite over A9s before the flop: 67.87% to 32.14% equity, counted exactly over every board, with the split by flop type and suit. If ATo and A9s get all the chips in before the flop, ATo owns 67.86% of the pot in the long run and A9s owns 32.14%. ## A9s against ATo: the numbers **Exact preflop results for A9s against ATo, in percent** | Hand | Wins | Ties | Loses | Equity | | --- | --- | --- | --- | --- | | A9s | 27.079 | 10.113 | 62.808 | 32.135 | | ATo | 62.808 | 10.113 | 27.079 | 67.865 | The matchup pits a suited hand against an offsuit hand. Sharing a rank is the signature of a dominated hand, since the weaker hand is usually out-kicked when the shared rank shows up. ATo is the clear favorite, though A9s gets there on roughly one board in 3. Of every 100 boards, about 10.11 are split pots, and the equity figures already include them. In the ranking of all 169 starting hands, A9s is number 18 and ATo is number 19. **Boards behind the percentages: 61,642,944 counted in all** | Hand | Boards won, about | Boards tied, about | Boards lost, about | | --- | --- | --- | --- | | A9s | 16,692,000 | 6,234,000 | 38,717,000 | | ATo | 38,717,000 | 6,234,000 | 16,692,000 | The board total is exact, 36 deals at 1,712,304 boards each. Won, tied and lost counts are rounded to the nearest thousand from the five-decimal percentages. **A9s against ATo read as odds** | Hand | Equity as odds (to 1) | Wins one deal in | Loses one deal in | Pot odds needed to call (to 1) | | --- | --- | --- | --- | --- | | A9s | 0.474 | 3.693 | 1.592 | 2.112 | | ATo | 2.112 | 1.592 | 3.693 | 0.474 | 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: ATo holds 74.48% on rainbow flops topped by a ten or better and 60.10% on low rainbow flops (nine high or lower). ATo stays ahead on all five textures. **A9s against ATo by flop texture, in percent** | Flop | Share of flops | A9s wins | Ties | ATo wins | A9s equity | | --- | --- | --- | --- | --- | --- | | Rainbow, ten or higher | 23.905 | 21.269 | 8.510 | 70.221 | 25.524 | | Rainbow, nine or lower | 7.042 | 37.800 | 4.205 | 57.995 | 39.902 | | Two-tone | 46.527 | 29.036 | 7.086 | 63.878 | 32.579 | | Monotone | 5.192 | 32.920 | 7.467 | 59.613 | 36.653 | | Paired | 17.334 | 23.734 | 23.640 | 52.626 | 35.554 | 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 Relative to a random opponent, A9s changes by -30.64 points (baseline 62.78%) and ATo by +5.14 points (baseline 62.72%). **A9s and ATo 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 | | --- | --- | --- | --- | --- | | A9s, all flops | 32.135 | 62.781 | -30.646 | 0.51186 | | A9s, rainbow, ten or higher | 25.524 | 62.781 | -37.257 | 0.40656 | | A9s, rainbow, nine or lower | 39.902 | 62.781 | -22.879 | 0.63557 | | A9s, two-tone | 32.579 | 62.781 | -30.202 | 0.51893 | | A9s, monotone | 36.653 | 62.781 | -26.128 | 0.58382 | | A9s, paired | 35.554 | 62.781 | -27.227 | 0.56632 | | ATo, all flops | 67.865 | 62.722 | +5.143 | 1.08200 | | ATo, rainbow, ten or higher | 74.476 | 62.722 | +11.754 | 1.18740 | | ATo, rainbow, nine or lower | 60.098 | 62.722 | -2.624 | 0.95816 | | ATo, two-tone | 67.421 | 62.722 | +4.699 | 1.07492 | | ATo, monotone | 63.347 | 62.722 | +0.625 | 1.00996 | | ATo, paired | 64.446 | 62.722 | +1.724 | 1.02749 | ## Does a shared suit matter? Suit overlap shows up in the numbers. With a suit in common ATo has 68.65% equity, and with none in common it has 67.47%. ATo does better with a shared suit, by 1.18 points. **A9s against ATo by suit overlap, in percent** | Deals | Specific deals | Share of deals | A9s wins | Ties | ATo wins | A9s equity | | --- | --- | --- | --- | --- | --- | --- | | Share a suit | 12 | 33.33 | 26.226 | 10.240 | 63.534 | 31.346 | | No shared suit | 24 | 66.67 | 27.505 | 10.049 | 62.446 | 32.530 | ## How often this matchup comes up Exactly 36 specific deals fit this matchup in one seat order, which is 0.0022% of 1,624,350; both orders together give 72, or 0.0044%. ## A worked example Put $100 each into a $200 pot and deal every board once: ATo averages $135.72 back, ahead of its $100 by $35.72, while A9s averages $64.28, short of its $100 by $35.72. In 1,000 deals of exactly this matchup, expect about 628 won outright by ATo, about 271 won outright by A9s and about 101 split. ## The same matchup from the other side If you came looking for ATo against A9s, the numbers are the same with the hands swapped: 67.86% and 32.14%. ## Keep exploring As9s against AhTd 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 As9s against AhTd in the equity calculator](https://georgelipoker.com/tools/equity-calculator.md#p1=As9s&p2=AhTd) - [A9s combos](https://georgelipoker.com/combos/a9s.md) - [ATo combos](https://georgelipoker.com/combos/ato.md) - [A9s vs KJs](https://georgelipoker.com/equity/a9s-vs-kjs.md) - [A9s vs A8s](https://georgelipoker.com/equity/a9s-vs-a8s.md) - [66 vs ATo](https://georgelipoker.com/equity/66-vs-ato.md) - [All hand matchups](https://georgelipoker.com/equity.md) ## How this was computed The figures are counted, not estimated: 1,712,304 boards for every suit pattern of the 36 specific deals, with both seven-card hands compared each time. Equity gives half a win for a tie. For the flop rows, a board is counted once under each of the ten flops inside it. Source: our own exact count from the GeorgeLiPoker poker math library. No outside data is used. ## Related - [A9s vs KJs: preflop equity](https://georgelipoker.com/equity/a9s-vs-kjs.md) - [A9s vs A8s: preflop equity](https://georgelipoker.com/equity/a9s-vs-a8s.md) - [66 vs ATo: preflop equity](https://georgelipoker.com/equity/66-vs-ato.md)