Verdict
Call
18 outs, flop, half-pot bet
- Chance to hit by the rivertwo cards to come62.44%
- Equity the call needs$50 into a pot of $20025.00%
- Margin over the priceyour chance minus the price+37.44 points
How the verdict is reached
Your draw is priced at 25.00% and it arrives 62.44% of the time. A lead of 37.44 points is wide enough that the call stands even if the numbers shift a little.
A count of 18 outs is usually the sum of more than one draw. Out of 47 unseen cards, one card helps 38.30% of the time.
A $100 pot, step by step
- Pot when the bet arrives$100
- Bet$50
- Cost to call$50
- Final pot if you call$200
- What a hit wins$150
- You lose on a miss$50
- Probability of a hit62.44%
- Expected value of calling+$74.88
- Equity the call needs25.00%
- Exact margin over the price+37.4422 points
- Break-even count of outs6.23 outs
- Your outs minus break-even outs+11.77 outs
Assume the whole pot goes to you when you hit, the call is lost when you miss, and nothing more is bet. Calling then gains $74.88 on average: $93.66 from hits, minus $18.78 from misses, +1.498 per dollar called.
Written as odds, the pot lays 3 : 1 while the draw is 0.6 : 1 against.
Watch the pot you divide by. Leaving your call out turns 25.00% into 33.33%, and the margin into +29.1088 points. Dividing by the starting pot gives 50.00% and a margin of +12.4422 points, further from the truth.
Where the call would flip
The call survives losing up to 11 outs. At 7 outs the chance is 27.84%, just enough for 25.00%.
Reverse implied odds are the risk here. A hit that costs you $119.93 later, 2.40 times your call, is where the call stops being worth it.
| Given back later | Price with it | Your chance minus price | Value of the call | Call? |
|---|---|---|---|---|
| $0 | 25.00% | +37.44 points | +$74.88 | Call |
| $10 | 26.32% | +36.13 points | +$68.64 | Call |
| $25 | 28.57% | +33.87 points | +$59.27 | Call |
| $50 | 33.33% | +29.11 points | +$43.66 | Call |
| $100 | 50.00% | +12.44 points | +$12.44 | Call |
Two views of the same draw
No conflict here: 62.44% for two cards and 38.30% for one both give a call against the 25.00% price, so you need not decide which view applies.
| Cards counted | Chance | Margin over price | Value of the call | Verdict |
|---|---|---|---|---|
| By the river, two cards | 62.44% | +37.4422 points | +$74.88 | Call |
| Next card only | 38.30% | +13.2979 points | +$26.60 | Call |
Nearby draws
A few outs either way, against a half-pot bet that needs 25.00%. The chance climbs about 2.59 points with each extra out.
How bet size moves the answer
Bet size sets the price, so the verdict changes as you scan the table. The half-pot bet of this page is marked in the first column.
Nothing in the list is too big to call: 18 outs reach 62.44% on the flop, above every price on the page.
| Bet size | Equity needed | Margin | Verdict |
|---|---|---|---|
| quarter-pot | 16.67% | +45.78 points | Call |
| third-pot | 20.00% | +42.44 points | Call |
| two-fifths-pot | 22.22% | +40.22 points | Call |
| half-pot, this page | 25.00% | +37.44 points | Call |
| two-thirds-pot | 28.57% | +33.87 points | Call |
| three-quarter-pot | 30.00% | +32.44 points | Call |
| pot-size | 33.33% | +29.11 points | Call |
| 1.25x-pot | 35.71% | +26.73 points | Call |
| 1.5x-pot | 37.50% | +24.94 points | Call |
| 2x-pot | 40.00% | +22.44 points | Call |
| 3x-pot | 42.86% | +19.59 points | Call |
| 4x-pot | 44.44% | +18.00 points | Call |
How this is computed
The hit chance comes straight from combinations. Out of 1,081 pairs of unseen cards, 406 miss every out, so you hit 62.44% of the time.
The numbers are a baseline rather than a prediction for one hand. The price is 25.00%, from $50 into $200, and the chance assumes a whole pot won on a hit, no more betting, 47 equally likely unseen cards, and no cards removed for the other player.
Computed from the closed form by the GeorgeLiPoker math library.
Updated
Questions
What is the right play with 18 outs when a half-pot bet comes on the flop?
Reduce the question to a comparison of two numbers: 62.44% to hit and 25.00% to break even. The first minus the second is +37.44 points, which makes this a call, and the call averages +$74.88 on a $100 pot if no more betting follows.
How many outs are enough to continue against a bet of half the pot on the flop?
A call starts to work at 7 outs: 27.84% to hit versus 25.00% needed. One out fewer drops the chance to 24.14%. You hold 18, which is 11 more than the minimum.
One card or two: which number belongs next to the 25.00% price?
Use the by-the-river chance, 62.44%, when no more betting follows, and the next-card chance, 38.30%, when you must pay again on the turn. Against the 25.00% price both give a call, so the choice does not change the play here.
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