Poker Probability Basics: Combos & Frequency

Probability gives you a consistent way to compare ranges, draws, and calling decisions. The result is only as good as the assumptions about ranges and clean outs.

Combinations (Combos)

A combo is one specific way to hold a hand. Before accounting for visible-card blockers, there are:

16 combos of an unpaired rank combination: 4 suited plus 12 offsuit, such as AK
6 combos of a pocket pair: such as AA
4 combos of a specific suited hand: such as AKs

Visible cards remove combinations. For example, if an ace is on the board, fewer AA and Ax combinations remain possible.

Basic Frequency Concepts

Pot Odds: After a $50 bet into a $100 pot, you call $50 to contest a final $200 pot, which is a 3:1 reward-to-call ratio
Required Equity: The same call needs 50 / 200 = 25% equity before considering future action
Break-Even Percentage: call / (pot before the bet + bet + call)

Counting Outs

Outs are unseen cards that improve your hand to a likely winner; discount dirty outs
Rule of 2 and 4: Multiply clean outs by about 4 from flop to river, or by about 2 with one card to come
Nine clean flush outs are about 35% from flop to river and about 19.6% from turn to river

Practical Application

Use combo counting on a clearly defined range. AA and KK contain 12 combinations before blockers: 6 combinations of each pair. A visible ace or king removes some combinations, which changes the weight of that value region.