Hitting Soft 17 in Blackjack

Blackjack basic strategy dictates that players should always hit on soft 17, yet most are reluctant to do so, making the natural assumption that the odds of winning will be improved by standing rather than decreasing the value of the hand with added hits.

Once again, a simple explanation of the gambling mathematics behind basic blackjack strategy can be very useful in understanding why it's advisable to always hit on soft 17.

Standing

In blackjack, a hand value of seventeen is weak from the start. Let's look at the odds for the outcomes of the dealer's hand irrespective of the cards originally dealt:

  • Seventeen: 14.61%
  • Eighteen: 13.87%
  • Nineteen: 13.27%
  • Twenty: 18.12%
  • Twenty one: 6.99%
  • Bust: 33.15%

From these figures we can see that if you elect to stand on a seventeen of any composition, you will have a mere 33.15% chance of winning because the dealer will have to bust for you to stand a chance of winning at all.

Even if you count the 14.61% chance of a push turning to your favour, there is still a 52.24% chance of losing. With this level of risk, even if there is an even-money payout for a win, the casino will still have an advantage of approximately 20% over you if you choose to stand on 17.

Hitting

If you're holding a hard 17 it makes little sense to hit. This is due to the fact that there are only 4 thirteen cards and just 30.76% chance of improving the hand value, which leaves you with a 69.24% chance of busting.

A soft 17 is different because the Ace can revert to the value of one, so the four 10 value cards pose no risk as drawing one of these will leave you no worse off than you started. So from just a single hit, the odds of drawing a hand with a value between 17 and 21 are 8 in 13, or 61.53%.

On the flip side, of the remaining 38.47% possible outcomes, the immediate result of your hand will range between a twelve and sixteen total. And even if it becomes necessary for you to take additional hits, there is still a 44.85% that you will hit a tenable hand.

Ultimately the probable odds of hitting on soft 17 are as follows:

  • Seventeen: 34.22%
  • Eighteen: 11.44%
  • Nineteen: 11.44%
  • Twenty: 11.14%
  • Twenty One: 11.14%
  • Bust: 21.21%

If you hit on soft 17, you will stand a 21.21% chance of busting as opposed to zero if you choose to stand, however you will also have a 44.56% chance of improving your hand for the win.

While the player who hits a soft 17 does run the risk of busting (21.21% as compared to 0% if he'd stood), he has a much greater chance of improving the hand (44.56% as compared to 0%).

The house edge of 20% is also reduced to less than 5%, so hitting when holding soft 17 is always the way to go.

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