How to Calculate Equity in Poker by Hand

Equity is the share of the pot your hand wins on average if the hand goes to showdown, written as a percentage. To calculate it by hand you count your outs — the unseen cards that make you the winner — and translate that count into a win probability. A flush draw wins about 36 percent of the time from the flop; that 36 percent is its equity.

Counting outs, honestly

An out is any card left in the deck that turns your hand into the likely best one. The common draws are worth memorizing:

• Flush draw — 13 cards of the suit, minus the 4 you can see, leaves 9 outs.
• Open-ended straight draw — two ranks complete it, four of each, so 8 outs.
• Gutshot — one rank completes it, 4 outs.

The honesty part matters. If the card that fills your straight also puts a third flush card on the board, it may hand your opponent a stronger hand — that out is tainted, and you should not count it fully. Overcounting outs is the most common way a by-hand estimate goes wrong.

The rule of 2 and 4

With a clean out count, one shortcut does the conversion:

• Flop, two cards to come: outs × 4.
• One card to come (turn to river, or flop when you’ll only pay for the turn): outs × 2.

So 9 flush outs is roughly 9 × 4 = 36 percent by the river from the flop, or 9 × 2 = 18 percent for the turn card alone. Eight straight outs run about 32 percent and 16 percent. Multiplying by 4 drifts a little high once you have many outs — with 12-plus outs, subtract a couple of points — but for live decisions it is close enough to act on.

Where this becomes a real decision is against pot odds: equity tells you how often you win, and the price the pot offers tells you how often you need to. That comparison is covered in the odds and math material, and the exact range-versus-range math that is too heavy to do in your head is what a poker equity calculator is for. See the wider kit in tools & software.