--- title: "ATo vs A4s: preflop equity" url: "https://georgelipoker.com/equity/ato-vs-a4s.md" canonical_url: "https://georgelipoker.com/equity/ato-vs-a4s" last_updated: "2026-10-23" type: "reference" summary: "ATo is a big favorite over A4s before the flop: 66.19% to 33.81% equity, counted exactly over every board, with the split by flop type and suit." related: ["https://georgelipoker.com/equity/ato-vs-a3s.md", "https://georgelipoker.com/equity/ato-vs-qjo.md", "https://georgelipoker.com/equity/kjs-vs-a4s.md"] --- # ATo vs A4s: preflop equity ATo is a big favorite over A4s before the flop: 66.19% to 33.81% equity, counted exactly over every board, with the split by flop type and suit. Over all 1,712,304 boards that can follow this deal, ATo finishes with 66.19% of the pot and A4s with 33.81%. ## ATo against A4s: the numbers **Exact preflop results for ATo against A4s, in percent** | Hand | Wins | Ties | Loses | Equity | | --- | --- | --- | --- | --- | | ATo | 61.048 | 10.292 | 28.660 | 66.194 | | A4s | 28.660 | 10.292 | 61.048 | 33.806 | Here an offsuit hand (ATo) meets a suited hand (A4s). Sharing a rank is the signature of a dominated hand, since the weaker hand is usually out-kicked when the shared rank shows up. A lead of 32.38 points is large but not decisive: A4s still takes about 287 of every 1,000 deals. Split pots make up 10.29% of the boards, and both equity figures count them as half a win each. ATo ranks number 19 of 169 starting hands, and A4s ranks number 35, by equity against a random hand. **Boards behind the percentages: 61,642,944 counted in all** | Hand | Boards won, about | Boards tied, about | Boards lost, about | | --- | --- | --- | --- | | ATo | 37,632,000 | 6,344,000 | 17,667,000 | | A4s | 17,667,000 | 6,344,000 | 37,632,000 | Exact total: 36 deals times 1,712,304 boards. The other three counts come from the five-decimal percentages and are rounded to the nearest thousand, so read them as approximate. **ATo 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) | | --- | --- | --- | --- | --- | | ATo | 1.958 | 1.638 | 3.489 | 0.511 | | A4s | 0.511 | 3.489 | 1.638 | 1.958 | 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 By flop texture, ATo's equity runs from 54.41% on low rainbow flops (nine high or lower) up to 73.40% on rainbow flops topped by a ten or better. ATo stays ahead on all five textures, but the swing between them is large, so how the flop looks matters a great deal. **ATo against A4s by flop texture, in percent** | Flop | Share of flops | ATo wins | Ties | A4s wins | ATo equity | | --- | --- | --- | --- | --- | --- | | Rainbow, ten or higher | 23.905 | 69.077 | 8.642 | 22.281 | 73.398 | | Rainbow, nine or lower | 7.042 | 52.389 | 4.044 | 43.567 | 54.411 | | Two-tone | 46.527 | 61.929 | 7.184 | 30.887 | 65.521 | | Monotone | 5.192 | 58.353 | 7.621 | 34.026 | 62.163 | | Paired | 17.334 | 51.932 | 24.250 | 23.818 | 64.057 | Rainbow flops have three suits, two-tone flops repeat one suit, monotone flops are all one suit, and paired flops repeat a rank. ## Compared with a random hand Compared with a random opponent, this matchup shifts ATo from 62.72% by +3.47 points and A4s from 59.03% by -25.22 points. **ATo 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 | | --- | --- | --- | --- | --- | | ATo, all flops | 66.194 | 62.722 | +3.472 | 1.05536 | | ATo, rainbow, ten or higher | 73.398 | 62.722 | +10.676 | 1.17021 | | ATo, rainbow, nine or lower | 54.411 | 62.722 | -8.311 | 0.86749 | | ATo, two-tone | 65.521 | 62.722 | +2.799 | 1.04463 | | ATo, monotone | 62.163 | 62.722 | -0.559 | 0.99109 | | ATo, paired | 64.057 | 62.722 | +1.335 | 1.02128 | | A4s, all flops | 33.806 | 59.034 | -25.228 | 0.57265 | | A4s, rainbow, ten or higher | 26.602 | 59.034 | -32.432 | 0.45062 | | A4s, rainbow, nine or lower | 45.589 | 59.034 | -13.445 | 0.77225 | | A4s, two-tone | 34.479 | 59.034 | -24.555 | 0.58405 | | A4s, monotone | 37.837 | 59.034 | -21.197 | 0.64094 | | A4s, paired | 35.943 | 59.034 | -23.091 | 0.60885 | ## Does a shared suit matter? Of the deals of this matchup, 12 share a suit (ATo at 66.99%) and 24 do not (65.79%). ATo does better with a shared suit, by 1.20 points. **ATo against A4s by suit overlap, in percent** | Deals | Specific deals | Share of deals | ATo wins | Ties | A4s wins | ATo equity | | --- | --- | --- | --- | --- | --- | --- | | Share a suit | 12 | 33.33 | 61.781 | 10.423 | 27.796 | 66.992 | | No shared suit | 24 | 66.67 | 60.681 | 10.227 | 29.092 | 65.794 | ## How often this matchup comes up How often does it happen? 36 of the 1,624,350 ordered deals (0.0022%) are ATo against A4s, and 72 (0.0044%) if either hand may sit in either seat. ## A worked example Try it with money: two players each put in $100 and the whole board runs out every possible way. ATo averages $132.38 from the $200, up $32.38; A4s averages $67.62, down $32.38. In 1,000 deals of exactly this matchup, expect about 610 won outright by ATo, about 287 won outright by A4s and about 103 split. ## The same matchup from the other side One page covers both views. From A4s' side the equity is 33.81%, and from ATo's side it is 66.19%. ## Keep exploring Open the calculator with AsTh against Ad4d 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 Ad4d in the equity calculator](https://georgelipoker.com/tools/equity-calculator.md#p1=AsTh&p2=Ad4d) - [ATo combos](https://georgelipoker.com/combos/ato.md) - [A4s combos](https://georgelipoker.com/combos/a4s.md) - [ATo vs A3s](https://georgelipoker.com/equity/ato-vs-a3s.md) - [ATo vs QJo](https://georgelipoker.com/equity/ato-vs-qjo.md) - [KJs vs A4s](https://georgelipoker.com/equity/kjs-vs-a4s.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 36 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 A3s: preflop equity](https://georgelipoker.com/equity/ato-vs-a3s.md) - [ATo vs QJo: preflop equity](https://georgelipoker.com/equity/ato-vs-qjo.md) - [KJs vs A4s: preflop equity](https://georgelipoker.com/equity/kjs-vs-a4s.md)