--- title: "A9o vs A4s: preflop equity" url: "https://georgelipoker.com/equity/a9o-vs-a4s.md" canonical_url: "https://georgelipoker.com/equity/a9o-vs-a4s" last_updated: "2026-10-23" type: "reference" summary: "A9o is a big favorite over A4s before the flop: 63.93% to 36.07% equity, counted exactly over every board, with the split by flop type and suit." related: ["https://georgelipoker.com/equity/a9o-vs-a3s.md", "https://georgelipoker.com/equity/a9o-vs-qjo.md", "https://georgelipoker.com/equity/kjo-vs-a4s.md"] --- # A9o vs A4s: preflop equity A9o is a big favorite over A4s before the flop: 63.93% to 36.07% equity, counted exactly over every board, with the split by flop type and suit. If A9o and A4s get all the chips in before the flop, A9o owns 63.93% of the pot in the long run and A4s owns 36.07%. ## A9o against A4s: the numbers **Exact preflop results for A9o against A4s, in percent** | Hand | Wins | Ties | Loses | Equity | | --- | --- | --- | --- | --- | | A9o | 56.435 | 14.986 | 28.579 | 63.928 | | A4s | 28.579 | 14.986 | 56.435 | 36.072 | Here an offsuit hand (A9o) meets a suited hand (A4s). Because the hands share one rank, the one with the higher kicker is ahead when that rank pairs and the other hand is mostly drawing. The lead is steady rather than large, and the flop still has plenty of say in who wins. Of every 100 boards, about 14.99 are split pots, and the equity figures already include them. Ranked by equity against a random hand, A9o is number 25 of the 169 starting hands and A4s is number 35. **Boards behind the percentages: 61,642,944 counted in all** | Hand | Boards won, about | Boards tied, about | Boards lost, about | | --- | --- | --- | --- | | A9o | 34,788,000 | 9,238,000 | 17,617,000 | | A4s | 17,617,000 | 9,238,000 | 34,788,000 | The total is exact: 36 specific deals times 1,712,304 boards. The three counts are approximate, worked out from the percentages to five decimals and rounded to the nearest thousand. **A9o against A4s read as odds** | Hand | Equity as odds (to 1) | Wins one deal in | Loses one deal in | Pot odds needed to call (to 1) | | --- | --- | --- | --- | --- | | A9o | 1.772 | 1.772 | 3.499 | 0.564 | | A4s | 0.564 | 3.499 | 1.772 | 1.772 | The last column is the smallest pot odds, written as a pot-to-call ratio, at which a call breaks even with this equity. ## Who is ahead on which flops Across the five flop textures A9o's equity moves by 7.52 points, from 60.40% on paired flops to 67.92% on rainbow flops topped by a ten or better. A9o stays ahead on all five textures. **A9o against A4s by flop texture, in percent** | Flop | Share of flops | A9o wins | Ties | A4s wins | A9o equity | | --- | --- | --- | --- | --- | --- | | Rainbow, ten or higher | 24.588 | 60.834 | 14.177 | 24.989 | 67.922 | | Rainbow, nine or lower | 6.360 | 61.649 | 3.506 | 34.845 | 63.402 | | Two-tone | 46.527 | 57.933 | 11.264 | 30.803 | 63.565 | | Monotone | 5.192 | 55.350 | 10.654 | 33.996 | 60.677 | | Paired | 17.333 | 44.586 | 31.634 | 23.780 | 60.403 | 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 60.77%, A9o changes by +3.16 points, and A4s, from 59.03%, by -22.96. **A9o and A4s 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 | | --- | --- | --- | --- | --- | | A9o, all flops | 63.928 | 60.773 | +3.155 | 1.05191 | | A9o, rainbow, ten or higher | 67.922 | 60.773 | +7.149 | 1.11763 | | A9o, rainbow, nine or lower | 63.402 | 60.773 | +2.629 | 1.04326 | | A9o, two-tone | 63.565 | 60.773 | +2.792 | 1.04594 | | A9o, monotone | 60.677 | 60.773 | -0.096 | 0.99842 | | A9o, paired | 60.403 | 60.773 | -0.370 | 0.99391 | | A4s, all flops | 36.072 | 59.034 | -22.962 | 0.61104 | | A4s, rainbow, ten or higher | 32.078 | 59.034 | -26.956 | 0.54338 | | A4s, rainbow, nine or lower | 36.598 | 59.034 | -22.436 | 0.61995 | | A4s, two-tone | 36.435 | 59.034 | -22.599 | 0.61719 | | A4s, monotone | 39.323 | 59.034 | -19.711 | 0.66611 | | A4s, paired | 39.597 | 59.034 | -19.437 | 0.67075 | ## Does a shared suit matter? The suit split reads 64.72% for A9o with a shared suit and 63.54% without one. A9o does better with a shared suit, by 1.18 points. **A9o against A4s by suit overlap, in percent** | Deals | Specific deals | Share of deals | A9o wins | Ties | A4s wins | A9o equity | | --- | --- | --- | --- | --- | --- | --- | | Share a suit | 12 | 33.33 | 57.142 | 15.145 | 27.713 | 64.715 | | No shared suit | 24 | 66.67 | 56.081 | 14.907 | 29.012 | 63.535 | ## How often this matchup comes up This page stands for 36 specific-card matchups (0.0022% of 1,624,350 ordered deals), or 72 once you count the seats both ways (0.0044%). ## A worked example Worked example: both players commit $100, so $200 sits in the middle. Over every board, A9o's average share is $127.86 (a gain of $27.86) and A4s' is $72.14 (a loss of $27.86). Over a long run, 1,000 deals split into about 564 for A9o, 286 for A4s and 150 tied. ## The same matchup from the other side The mirror image, A4s against A9o, is 36.07% to 63.93%, and its address redirects to this page. ## Keep exploring Try As9h against Ad4d in the calculator: the hands share no suit, and every card can be changed. The links after it are the closest matchups in the ranking. - [Open As9h against Ad4d in the equity calculator](https://georgelipoker.com/tools/equity-calculator.md#p1=As9h&p2=Ad4d) - [A9o combos](https://georgelipoker.com/combos/a9o.md) - [A4s combos](https://georgelipoker.com/combos/a4s.md) - [A9o vs A3s](https://georgelipoker.com/equity/a9o-vs-a3s.md) - [A9o vs QJo](https://georgelipoker.com/equity/a9o-vs-qjo.md) - [KJo vs A4s](https://georgelipoker.com/equity/kjo-vs-a4s.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 - [A9o vs A3s: preflop equity](https://georgelipoker.com/equity/a9o-vs-a3s.md) - [A9o vs QJo: preflop equity](https://georgelipoker.com/equity/a9o-vs-qjo.md) - [KJo vs A4s: preflop equity](https://georgelipoker.com/equity/kjo-vs-a4s.md)