--- title: "66 vs A4s: preflop equity" url: "https://georgelipoker.com/equity/66-vs-a4s.md" canonical_url: "https://georgelipoker.com/equity/66-vs-a4s" last_updated: "2026-10-23" type: "reference" summary: "66 is a big favorite over A4s before the flop: 65.80% to 34.20% equity, counted exactly over every board, with the split by flop type and suit." related: ["https://georgelipoker.com/equity/66-vs-a3s.md", "https://georgelipoker.com/equity/66-vs-qjo.md", "https://georgelipoker.com/equity/a9s-vs-a4s.md"] --- # 66 vs A4s: preflop equity 66 is a big favorite over A4s before the flop: 65.80% to 34.20% equity, counted exactly over every board, with the split by flop type and suit. If 66 and A4s get all the chips in before the flop, 66 owns 65.80% of the pot in the long run and A4s owns 34.20%. ## 66 against A4s: the numbers **Exact preflop results for 66 against A4s, in percent** | Hand | Wins | Ties | Loses | Equity | | --- | --- | --- | --- | --- | | 66 | 65.567 | 0.469 | 33.964 | 65.801 | | A4s | 33.964 | 0.469 | 65.567 | 34.199 | 66 is a pocket pair and A4s is a suited hand. One of the other hand's cards outranks the pair and one is below it, which makes this a closer race than a pair against two small cards. A lead of 31.60 points is large but not decisive: A4s still takes about 339 of every 1,000 deals. Ties are 0.47% of the outcomes here; each tied board gives both hands half the pot. For context, 66 sits at number 17 of 169 starting hands and A4s at number 35 when each is run against a random hand. **Boards behind the percentages: 41,095,296 counted in all** | Hand | Boards won, about | Boards tied, about | Boards lost, about | | --- | --- | --- | --- | | 66 | 26,945,000 | 193,000 | 13,958,000 | | A4s | 13,958,000 | 193,000 | 26,945,000 | The total is exact: 24 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. **66 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) | | --- | --- | --- | --- | --- | | 66 | 1.924 | 1.525 | 2.944 | 0.520 | | A4s | 0.520 | 2.944 | 1.525 | 1.924 | 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 66 prefers low rainbow flops (nine high or lower), where it holds 78.38%, and likes monotone flops least, where it holds 62.32%. 66 stays ahead on all five textures, but the swing between them is large, so how the flop looks matters a great deal. **66 against A4s by flop texture, in percent** | Flop | Share of flops | 66 wins | Ties | A4s wins | 66 equity | | --- | --- | --- | --- | --- | --- | | Rainbow, ten or higher | 25.220 | 65.469 | 0.251 | 34.280 | 65.594 | | Rainbow, nine or lower | 5.689 | 78.009 | 0.733 | 21.258 | 78.375 | | Two-tone | 46.545 | 64.620 | 0.311 | 35.069 | 64.775 | | Monotone | 5.212 | 61.080 | 2.483 | 36.437 | 62.321 | | Paired | 17.334 | 65.516 | 0.519 | 33.965 | 65.775 | Flop types: rainbow means three different suits, two-tone means one suit twice, monotone means one suit three times, paired means a repeated rank. ## Compared with a random hand A random hand would give 66 63.29% and A4s 59.03%. Against each other the change is +2.51 points for 66 and -24.83 for A4s. **66 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 | | --- | --- | --- | --- | --- | | 66, all flops | 65.801 | 63.285 | +2.516 | 1.03976 | | 66, rainbow, ten or higher | 65.594 | 63.285 | +2.309 | 1.03649 | | 66, rainbow, nine or lower | 78.375 | 63.285 | +15.090 | 1.23845 | | 66, two-tone | 64.775 | 63.285 | +1.490 | 1.02354 | | 66, monotone | 62.321 | 63.285 | -0.964 | 0.98477 | | 66, paired | 65.775 | 63.285 | +2.490 | 1.03935 | | A4s, all flops | 34.199 | 59.034 | -24.835 | 0.57931 | | A4s, rainbow, ten or higher | 34.406 | 59.034 | -24.628 | 0.58282 | | A4s, rainbow, nine or lower | 21.625 | 59.034 | -37.409 | 0.36631 | | A4s, two-tone | 35.225 | 59.034 | -23.809 | 0.59669 | | A4s, monotone | 37.679 | 59.034 | -21.355 | 0.63826 | | A4s, paired | 34.225 | 59.034 | -24.809 | 0.57975 | ## Does a shared suit matter? Split by suits, the deals give 66 66.08% when the hands overlap in a suit and 65.52% when they do not. 66 does better with a shared suit, by 0.56 points. **66 against A4s by suit overlap, in percent** | Deals | Specific deals | Share of deals | 66 wins | Ties | A4s wins | 66 equity | | --- | --- | --- | --- | --- | --- | --- | | Share a suit | 12 | 50.00 | 65.828 | 0.512 | 33.660 | 66.084 | | No shared suit | 12 | 50.00 | 65.305 | 0.426 | 34.269 | 65.518 | ## How often this matchup comes up Out of 1,624,350 ways to deal two seats two cards each, 24 are 66 in one seat and A4s in the other (0.0015%); with the seats swapped too, 48 (0.0030%). ## A worked example Take a $200 pot built from $100 each. 66's equity of 65.80% is worth $131.60, a $31.60 edge, and A4s' 34.20% is worth $68.40, which is $31.60 under its stake. Scaled to 1,000 deals, that is roughly 656 wins for 66, 339 for A4s and 5 chopped pots. ## The same matchup from the other side Swap the hands and you get A4s with 34.20% against 66 with 65.80%. We keep one page per matchup, with the better-ranked hand first. ## Keep exploring 6s6h against Ad4d 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 6s6h against Ad4d in the equity calculator](https://georgelipoker.com/tools/equity-calculator.md#p1=6s6h&p2=Ad4d) - [66 combos](https://georgelipoker.com/combos/66.md) - [A4s combos](https://georgelipoker.com/combos/a4s.md) - [66 vs A3s](https://georgelipoker.com/equity/66-vs-a3s.md) - [66 vs QJo](https://georgelipoker.com/equity/66-vs-qjo.md) - [A9s vs A4s](https://georgelipoker.com/equity/a9s-vs-a4s.md) - [All hand matchups](https://georgelipoker.com/equity.md) ## How this was computed We counted every case. Each suit pattern of the 24 specific 66 against A4s deals meets all 1,712,304 boards, and the better five-card hand wins; a split pot is half a win each. The flop table reads each board under all ten of its three-card flops. Source: our own exact count from the GeorgeLiPoker poker math library. No outside data is used. ## Related - [66 vs A3s: preflop equity](https://georgelipoker.com/equity/66-vs-a3s.md) - [66 vs QJo: preflop equity](https://georgelipoker.com/equity/66-vs-qjo.md) - [A9s vs A4s: preflop equity](https://georgelipoker.com/equity/a9s-vs-a4s.md)