Odds of Aces vs Kings Preflop

Aces against kings is the classic preflop cooler, and the equity is one every player should know cold. All-in before the flop, pocket aces beat pocket kings about 82% of the time — kings win about 18%. That is roughly 4.5 to 1 in favor of aces. The number barely moves whether the hands are suited or not, so it is worth committing to memory.

The core equity

Run the two hands to a five-card board and aces come out 81.9% of the time, kings 18.1% (ties are negligible, well under 1%). Kings are drawing thin: their main equity comes from the two remaining kings in the deck plus the occasional straight or flush. Two outs on a single card is about 4%, but across a full five-card runout those outs compound, and the flush and straight backdoors push kings up to that 18%. This is why “cracking aces” with kings happens just often enough to sting.

Why the outs are worth 18%, not 4%

If kings had only their two-out shot on one card, the number would sit near 8% over two cards. The extra ten points come from runners: three cards of a suit for a backdoor flush, or four to a straight. Over five community cards these low-probability paths add up. For the full runout math and a card-by-card breakdown, see our detailed AA vs KK equity page. The lesson is that even a crushing favorite leaves the underdog real chances across a whole board.

A worked example

Both players are 100 big blinds deep. You open KK, an opponent three-bets, you four-bet, they shove aces, and you call. Before any cards come you are 18% to win the pot. If the pot is 200 big blinds, your share of equity is 0.18 × 200 = 36 big blinds — even as an underdog you “own” 36 BB of that pot in the long run. Fold instead and you realize 0%. That is why folding kings preflop for 100 BB is almost always wrong: you are surrendering 36 BB of equity to dodge an 18%-of-the-time bad beat. The pot is simply too big to pass, and kings are far too strong to lay down.

How often this specific clash happens

The setup is rare. A single named pair is 220 to 1 to be dealt (see pocket pair probability), and getting two specific pairs at one heads-up table is far rarer still — on the order of 1 in 22,000 hands for the exact AA-vs-KK meeting. At a nine-handed table the chance that some player holds AA while another holds KK on the same deal is meaningfully higher, but it is still a genuine cooler, not an everyday event. When it happens, it is usually the kings holder who remembers it.

How position and stack depth change the spot

The 82/18 equity is fixed, but the decision around it is not. Deep-stacked, kings should still get the money in preflop — you cannot fold an 18%-equity, second-best-possible pair when the pot is large. Short-stacked, the math is identical and the shove is trivial. The only spots where kings can consider folding are extreme ICM situations in a tournament near a big pay jump, and even then only against the tightest ranges. For a broader map of how pairs fare against each other, use our poker equity chart.

Common mistakes

• Slow-playing aces. With such a big edge you want the money in; getting cute lets kings realize backdoor equity for free.
• Folding kings to “avoid the cooler.” You cannot dodge variance by surrendering 36 BB of equity. Get it in.
• Overestimating the flip. This is not a coin flip — it is 4.5 to 1. Kings will lose four out of five times, so do not tilt when they do.

Quick reference

• AA equity vs KK: 82%.
• KK equity vs AA: 18%.
• Odds: about 4.5 to 1 for aces.
• Suited or offsuit: essentially the same.
• Frequency of the exact heads-up clash: roughly 1 in 22,000.

How the flop changes everything

The 82/18 split is only the starting point; the flop swings it hard. If a king flops, the kings holder rockets from 18% to roughly 96% — the two-outer arrives and now aces are the ones drawing thin. If the flop misses both hands, aces firm up toward the high 80s because kings have burned a street of their runner-outs. This is why neither player should ever fold preflop and why the money almost always goes in before the flop: once cards come, the equity can flip completely, but before the flop aces are a locked 4.5-to-1 favorite that no amount of caution can improve for the kings. Get it in, accept the variance, and let the long run pay you.

Know these five lines and the cooler will never surprise you. For the card-by-card derivation, read our AA vs KK equity breakdown.