What is the +2 rule in poker?

A quick way to work out pot odds. If the bet is one k-th of the pot (k = pot divided by bet), the share of the final pot you need to win to break even on a call is 1 divided by (k + 2). For a half-pot bet k = 2, so you need 1/4 = 25%.

When you call, the final pot is the pot plus two bets: your opponent's bet and your call. Your call is one bet out of that final pot, so the equity you need is bet divided by (pot + 2 x bet).

What is the rule of 4 and 2?

Multiply your outs by 4 when two cards are still to come and you will see both (for example, all-in on the flop), or by 2 when you will see one card. It gives your rough chance of hitting.

Should I always fold when my odds are too low?

On pot odds alone, yes. In real games you can sometimes call a little light if you expect to win more chips later when you hit (implied odds), and you should be more careful if hitting could still lose to a better hand.

When to Call in Poker: the +2 Rule for Pot Odds

The whole thing in 3 steps

1

Price

Pot 100 · bet 50

k = pot ÷ bet = 2

1 ÷ (k + 2) = 1 ÷ 4

25%

you need to win

2

Chance

A♥K♥ flush draw

9 outs

× 2 (one card to come)

18%

you will win

3

Compare

18% vs 25%

Chance ≥ price → call

Chance < price → fold

FOLD

18% is less than 25%

Common prices: ⅓ pot → 20% · ½ pot → 25% · ¾ pot → 30% · pot → 33% · 2× pot → 40%

Common draws: flush 9 outs · open-ended straight 8 · gutshot 4 | × 2 for one card to come, × 4 when all-in on the flop

Practise it now ↓How to work out k →

Step 1 in detail: the price (+2 rule)

Work out how many times the bet fits into the pot. Call that number k.

k = pot ÷ bet

Equity needed = 1 ÷ (k + 2)

"One over k plus two"

Half-pot bet

Pot 100, bet 50 → k = 2

1 ÷ (2 + 2) = 1/4 = 25%

Third-pot bet

Pot 90, bet 30 → k = 3

1 ÷ (3 + 2) = 1/5 = 20%

Pot-sized bet

Pot 100, bet 100 → k = 1

1 ÷ (1 + 2) = 1/3 = 33%

Overbet (2× pot)

Pot 100, bet 200 → k = ½

1 ÷ (½ + 2) = 1/2.5 = 40%

Watch out: k is pot ÷ bet, not bet ÷ pot. For a ¾-pot bet, k = 1 ÷ ¾ = 4/3 (not ¾), so 1 ÷ (4/3 + 2) = 3/10 = 30%.

For awkward sizes like ⅔ or ¾ pot

If the bet is a/b of the pot, you need a ÷ (b + 2a). It is the same rule, just easier with fractions. For ¾ pot: 3 ÷ (4 + 6) = 3/10 = 30%. For ⅔ pot: 2 ÷ (3 + 4) = 2/7 ≈ 29%.

Try it: drag the bet sizePot before the bet: 100

PotTheir betYour call (your share)

Cheat sheet

Bet size	k	Equity needed
¼ pot	4	1/6 ≈ 17%
⅓ pot	3	1/5 = 20%
½ pot	2	1/4 = 25%
⅔ pot	3/2	2/7 ≈ 29%
¾ pot	4/3	3/10 = 30%
Pot	1	1/3 ≈ 33%
1.5× pot	2/3	3/8 ≈ 38%
2× pot	½	2/5 = 40%

"Pot" means the pot before this bet. If other players already called in front of you, add their calls to the pot. Bigger bets always need more equity, but never more than 50%.

Step 2 in detail: count your outs

Outs are the cards still in the deck that turn your hand into the winner. Count them, then use the rule of 4 and 2:

One card to come → outs × 2

On the turn, or on the flop when you will only see the turn before more betting.

Two cards to come → outs × 4

On the flop when you are all-in, so you will see both the turn and the river.

The rule slightly overestimates big draws (×4 with 15 outs says 60%, the exact chance is 54%). That is close enough to decide; the trainer below shows the exact number too.

Step 3: more worked hands

Beyond pot odds. If hitting will probably win you more chips later, you can call a little light (that is implied odds). If hitting could still leave you second best, be stricter. Start with the plain rule first; it is right most of the time.

Practice: call or fold?

Random spots with real cards. Work out the price and your chance, then decide. Every answer shows the working.

Want more? Open the full-page trainer.

For the curious: why "+2" works

When you call, you put chips in to win everything in the middle. If you would win often enough to pay for all your calls over time, the call is good. If not, it loses chips in the long run.

So the question is: what share of the final pot is my call? That share is the minimum chance of winning you need. It is called your pot odds (or break-even equity).

Example. The pot is 100. Your opponent bets 50. If you call 50, the pot becomes 100 + 50 + 50 = 200.

Your 50 is one quarter of 200, so you need to win at least 25% of the time.

Notice the final pot is the old pot plus two bets: theirs and yours. That is the "+2".

When to Call: the +2 Rule