--- title: "A4s vs K9o: preflop equity" url: "https://georgelipoker.com/equity/a4s-vs-k9o.md" canonical_url: "https://georgelipoker.com/equity/a4s-vs-k9o" last_updated: "2026-10-23" type: "reference" summary: "A4s is a big favorite over K9o before the flop: 60.93% to 39.07% equity, counted exactly over every board, with the split by flop type and suit." related: ["https://georgelipoker.com/equity/a4s-vs-q9s.md", "https://georgelipoker.com/equity/a4s-vs-jts.md", "https://georgelipoker.com/equity/a3s-vs-k9o.md"] --- # A4s vs K9o: preflop equity A4s is a big favorite over K9o before the flop: 60.93% to 39.07% equity, counted exactly over every board, with the split by flop type and suit. If A4s and K9o get all the chips in before the flop, A4s owns 60.93% of the pot in the long run and K9o owns 39.07%. ## A4s against K9o: the numbers **Exact preflop results for A4s against K9o, in percent** | Hand | Wins | Ties | Loses | Equity | | --- | --- | --- | --- | --- | | A4s | 60.684 | 0.486 | 38.830 | 60.927 | | K9o | 38.830 | 0.486 | 60.684 | 39.073 | The matchup pits a suited hand against an offsuit hand. Neither hand shares a rank with the other, so this is a contest of high cards, connection and suits. A4s is ahead, but K9o is far from dead: it takes 388 of every 1,000 deals outright. Split pots make up 0.49% of the boards, and both equity figures count them as half a win each. Among the 169 starting hands, A4s is number 35 and K9o is number 40 by strength against a random hand. **Boards behind the percentages: 82,190,592 counted in all** | Hand | Boards won, about | Boards tied, about | Boards lost, about | | --- | --- | --- | --- | | A4s | 49,877,000 | 399,000 | 31,915,000 | | K9o | 31,915,000 | 399,000 | 49,877,000 | 48 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. **A4s against K9o read as odds** | Hand | Equity as odds (to 1) | Wins one deal in | Loses one deal in | Pot odds needed to call (to 1) | | --- | --- | --- | --- | --- | | A4s | 1.559 | 1.648 | 2.575 | 0.641 | | K9o | 0.641 | 2.575 | 1.648 | 1.559 | 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 Split by what the flop looks like, A4s peaks at 65.87% on paired flops and bottoms out at 57.46% on monotone flops. A4s stays ahead on all five textures. **A4s against K9o by flop texture, in percent** | Flop | Share of flops | A4s wins | Ties | K9o wins | A4s equity | | --- | --- | --- | --- | --- | --- | | Rainbow, ten or higher | 24.665 | 59.243 | 0.176 | 40.581 | 59.331 | | Rainbow, nine or lower | 6.365 | 57.844 | 0.972 | 41.184 | 58.330 | | Two-tone | 46.667 | 60.545 | 0.313 | 39.142 | 60.702 | | Monotone | 5.212 | 56.260 | 2.403 | 41.337 | 57.462 | | Paired | 17.091 | 65.552 | 0.641 | 33.807 | 65.872 | 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 A4s from 59.03% by +1.90 points and K9o from 57.81% by -18.74 points. **A4s and K9o 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 | | --- | --- | --- | --- | --- | | A4s, all flops | 60.927 | 59.034 | +1.893 | 1.03207 | | A4s, rainbow, ten or higher | 59.331 | 59.034 | +0.297 | 1.00503 | | A4s, rainbow, nine or lower | 58.330 | 59.034 | -0.704 | 0.98807 | | A4s, two-tone | 60.702 | 59.034 | +1.668 | 1.02825 | | A4s, monotone | 57.462 | 59.034 | -1.572 | 0.97337 | | A4s, paired | 65.872 | 59.034 | +6.838 | 1.11583 | | K9o, all flops | 39.073 | 57.812 | -18.739 | 0.67586 | | K9o, rainbow, ten or higher | 40.669 | 57.812 | -17.143 | 0.70347 | | K9o, rainbow, nine or lower | 41.670 | 57.812 | -16.142 | 0.72078 | | K9o, two-tone | 39.298 | 57.812 | -18.514 | 0.67976 | | K9o, monotone | 42.538 | 57.812 | -15.274 | 0.73580 | | K9o, paired | 34.128 | 57.812 | -23.684 | 0.59033 | ## Does a shared suit matter? Two kinds of deal exist here. In 24 of them the hands share a suit and A4s holds 60.60%. In 24 they do not, and it holds 61.25%. A4s does better with no shared suit, by 0.65 points. **A4s against K9o by suit overlap, in percent** | Deals | Specific deals | Share of deals | A4s wins | Ties | K9o wins | A4s equity | | --- | --- | --- | --- | --- | --- | --- | | Share a suit | 24 | 50.00 | 60.337 | 0.528 | 39.135 | 60.601 | | No shared suit | 24 | 50.00 | 61.032 | 0.444 | 38.524 | 61.254 | ## How often this matchup comes up This page stands for 48 specific-card matchups (0.0030% of 1,624,350 ordered deals), or 96 once you count the seats both ways (0.0059%). ## A worked example Say each player puts $100 in before the flop, making a $200 pot. On average A4s takes back $121.86 of it, which is $21.86 more than it put in, and K9o takes back $78.14, $21.86 less than it put in. In 1,000 deals of exactly this matchup, expect about 607 won outright by A4s, about 388 won outright by K9o and about 5 split. ## The same matchup from the other side K9o against A4s adds nothing new: it is 39.07% for K9o and 60.93% for A4s, the same figures reversed. ## Keep exploring As4s against Kh9d 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 As4s against Kh9d in the equity calculator](https://georgelipoker.com/tools/equity-calculator.md#p1=As4s&p2=Kh9d) - [A4s combos](https://georgelipoker.com/combos/a4s.md) - [K9o combos](https://georgelipoker.com/combos/k9o.md) - [A4s vs Q9s](https://georgelipoker.com/equity/a4s-vs-q9s.md) - [A4s vs JTs](https://georgelipoker.com/equity/a4s-vs-jts.md) - [A3s vs K9o](https://georgelipoker.com/equity/a3s-vs-k9o.md) - [All hand matchups](https://georgelipoker.com/equity.md) ## How this was computed Method: exact enumeration. The 48 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 - [A4s vs Q9s: preflop equity](https://georgelipoker.com/equity/a4s-vs-q9s.md) - [A4s vs JTs: preflop equity](https://georgelipoker.com/equity/a4s-vs-jts.md) - [A3s vs K9o: preflop equity](https://georgelipoker.com/equity/a3s-vs-k9o.md)