Equity

Equity is the share of the pot a hand is entitled to on average: the percentage of the time it will win if the hand runs to showdown from here. It is the quantity every other piece of poker arithmetic is built on.

Pot equity

If a hand wins 40 per cent of the time against an opponent's, it has 40 per cent equity. In a pot of 100 that is an expected 40 — not a result that will ever be observed in a single hand, but the correct average over many.

Equity is always measured against something. Against one specific holding it is a clean calculation. Against an opponent's whole range it is a weighted average across every hand they could hold, which is the more useful figure and the harder one.

Estimating it at the table

The standard shortcut is the rule of four and two. Count the cards that improve your hand to a winner — the outs — and then:

- On the flop, with two cards still to come, multiply by four. - On the turn, with one card to come, multiply by two.

Nine outs for a flush draw on the flop gives roughly 36 per cent; on the turn, roughly 18 per cent. The approximation drifts upward of about twelve outs and it quietly assumes every out actually wins, which is not always true — a flush card that gives an opponent a full house is not an out. Used with that caveat it is accurate enough for a decision at the table.

Comparing it to the price

Equity on its own decides nothing. It becomes a decision when set against pot odds — the price being offered. Calling a pot-sized bet means putting in one unit to win three, so the call needs about 33 per cent equity to break even. A half-pot bet needs 25 per cent and a bet of twice the pot needs 40 per cent.

If the equity exceeds the required percentage, the call is profitable; if not, it is not — before accounting for what might be won on later streets, which is the separate matter of implied odds.

Fold equity is a different thing

Fold equity is the value gained from the chance that an opponent folds. It belongs to the aggressor and it does not exist for a caller. This is why a semi-bluff — betting a draw — can be correct even when the pot equity alone does not justify continuing: the hand wins either by improving or by the opponent giving up, and the two chances add together.

The distinction matters because conflating them is a common error. A hand with 35 per cent pot equity that is calling has 35 per cent; the same hand betting may be doing considerably better.

Realising it

A final caveat worth more than most of the arithmetic: equity is not the same as money won. Equity assumes the hand reaches showdown, and a hand played out of position against an aggressive opponent frequently does not — it gets bet off a draw, or faces a sizing that makes continuing unprofitable. This gap is called equity realisation, and it is why position is worth so much. The same two cards are worth more in the seat that acts last.