20 outs on the flop against a pot-size bet: call or fold

The numbers favor a call. 20 outs on the flop reach 67.53%, and a pot-size bet asks only for 33.33%.

Verdict

Call

20 outs, flop, pot-size bet

  • Chance to hit by the rivertwo cards to come67.53%
  • Equity the call needs$100 into a pot of $30033.33%
  • Margin over the priceyour chance minus the price+34.20 points

Chance against price

This is one of the easier spots. 20 outs on the flop reach 67.53% by the river, the pot-size bet asks for just 33.33%, and the 34.20-point margin favors the call.

A count of 20 outs is usually the sum of more than one draw. Out of 47 unseen cards, one card helps 42.55% of the time.

A $100 pot, step by step

  • Starting pot$100
  • The bet$100
  • Chips you put in$100
  • Pot after your call$300
  • What a hit wins$200
  • You lose on a miss$100
  • Probability of a hit67.53%
  • Expected value of calling+$102.59
  • Equity the call needs33.33%
  • Exact margin over the price+34.1967 points
  • Fractional outs at the price8.53 outs
  • Margin measured in outs+11.47 outs

Over many identical spots, with the whole pot won on every hit, the call lost on every miss and no extra betting, calling gains $102.59 on average. Hits bring in $135.06, misses cost $32.47, and the ratio is +1.026 per dollar called.

As odds, 0.48 : 1 against hitting meets pot odds of 2 : 1.

The correct pot to divide by includes your call. Without it the price reads 50.00% rather than 33.33%, and the margin reads +17.5301 points.

How much room the call has

Count how many outs the call needs: 9 reach the 33.33% price, and you have 20. That leaves 11 outs of slack.

Your margin is worth $151.92 in later losses. Past that, 1.52 times your call, folding would have been better.

Price of a pot-size call if you give money back after a hit, 20 outs on the flop
Given back laterPrice with itYour chance minus priceValue of the callCall?
$033.33%+34.20 points+$102.59Call
$1034.48%+33.05 points+$95.84Call
$2536.36%+31.17 points+$85.71Call
$5040.00%+27.53 points+$68.83Call
$10050.00%+17.53 points+$35.06Call

Two views of the same draw

Whether you count one card or two, the answer is a call. The river figure is 67.53%, the next-card figure is 42.55%, and both are measured against 33.33%.

20 outs against a pot-size bet, one view per row
Cards countedChanceMargin over priceValue of the callVerdict
By the river, two cards67.53%+34.1967 points+$102.59Call
Next card only42.55%+9.2199 points+$27.66Call

Counts close to yours

Remove a few outs and watch the verdict. Every out is worth about 2.50 points on the flop, and the price stays at 33.33%.

Outs 16 to 20 on the flop against a pot-size bet
OutsBy the riverMarginVerdict
16 outs56.98%+23.65 pointsCall
17 outs59.76%+26.43 pointsCall
18 outs62.44%+29.11 pointsCall
19 outs65.03%+31.70 pointsCall
20 outs, this page67.53%+34.20 pointsCall

How bet size moves the answer

How much does bet size matter? The price climbs from 16.67% to 44.44% across the list, while 20 outs stay at 67.53%.

Nothing in the list is too big to call: 20 outs reach 67.53% on the flop, above every price on the page.

20 outs on the flop against every bet size
Bet sizeEquity neededMarginVerdict
quarter-pot16.67%+50.86 pointsCall
third-pot20.00%+47.53 pointsCall
two-fifths-pot22.22%+45.31 pointsCall
half-pot25.00%+42.53 pointsCall
two-thirds-pot28.57%+38.96 pointsCall
three-quarter-pot30.00%+37.53 pointsCall
pot-size, this page33.33%+34.20 pointsCall
1.25x-pot35.71%+31.82 pointsCall
1.5x-pot37.50%+30.03 pointsCall
2x-pot40.00%+27.53 pointsCall
3x-pot42.86%+24.67 pointsCall
4x-pot44.44%+23.09 pointsCall

How this is computed

No sampling is involved. On the flop there are 1,081 pairs of unseen cards, and 351 of them contain no out, which leaves 67.53% for at least one out.

The numbers are a baseline rather than a prediction for one hand. The price is 33.33%, from $100 into $300, 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

Should you call a pot-size bet with 20 outs on the flop?

Reduce the question to a comparison of two numbers: 67.53% to hit and 33.33% to break even. The first minus the second is +34.20 points, which makes this a call, and the call averages +$102.59 on a $100 pot if no more betting follows.

What is the minimum number of outs for a pot-size bet on the flop?

Look for 9 outs. That is the smallest count whose chance, 34.97%, reaches the 33.33% price; 8 manages 31.45%. You have 20, so you are 11 ahead of the minimum.

Does it matter whether you count one card or two against a pot-size bet?

The river figure of 67.53% assumes no further betting; the next-card figure of 42.55% assumes you pay again on the turn. Against 33.33%, both say call, so you can use either.

Check your own hands against the numbers

Bring a hand you played and we will work through the price, the chance to hit and the decision together.

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