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# How Much Should You Bet at Blackjack?

19 July 1999

How Much Should You Bet at Blackjack?

Blackjack and other table game players face a dilemma when sizing their bets relative to the bankrolls they're willing to risk. Betting high increases the chance of going broke during a session of reasonable length. Betting low cuts the likelihood of winning enough to color-up and scoot away happy.

Some know from experience how to balance these factors to meet individual gambling criteria. For others, the laws of probability offer guidance. Alternate approaches to estimating "risk of ruin," one based on surviving a session and the other on meeting win goals before hitting loss limits, are the means employed.

The specifics depend on details of games and styles of play. But ballpark figures based on typical conditions are good enough for most purposes. Assume, therefore, that solid citizens play blackjack with rules and departures from basic strategy such that the house has 1 percent edge. Further suppose these players start rounds with some base amounts 60 percent of the time. And following hunches or whatnot, press to 1.5 times the base 30 percent of the time, and to twice the base the other 10 percent. Finally, say they're willing to spend up to four hours at a table, but will quit earlier if they achieve their win goals.

Prudent players typically consider the survival criterion first. Starting with bankrolls that seemed sensible at home, they don't want to go bust within the period they'd planned to be gambling.

To determine bet size, reckon that players typically receive 24 hands per shoe, three shoes per hour. In four hours, this would total 288 hands. Risk of ruin calculations for the survival criterion show that players sizing their base bets at 2 percent of their stakes could be 85 percent sure of not going belly-up. That is, they'd expect their bankrolls to last for at least four hours in 85 out of 100 such sessions. A \$250 bankroll could correspondingly accommodate a progression of \$5, \$7.50, and \$10; a \$500 bankroll would warrant \$10, \$15 and \$20.

The second criterion can be applied independently. But it's more useful to find chances of reaching typical profit goals before going broke, starting at the previously-found 2 percent. Risk of ruin based on a win goal shows players having 63 percent chance of success with targets equal to half their stakes, for instance trying for \$250 by betting \$10, \$15, and \$20 on a \$500 budget. This falls to 44 percent if they won't stop without matching their stakes, and 26 percent trying to win twice their bankrolls.

What if players are more cautious about staying in action? Maybe they start with \$500 and base bets of 1 percent -- \$5, \$7.50, and \$10. Their confidence in surviving for four hours rises from 85 to 99.75 percent. But, betting this little, they're less apt to meet various profit goals. Chances drop from 63 to 59 percent of pocketing \$250 before losing \$500, from 44 to 39 percent of earning \$500, and from 26 to 20 percent of winning \$1,000.

Wagers which are higher fractions of loss limits have the opposite effect. Base bets equal to 5 percent of a bankroll -- for instance, \$25 with a \$500 stake -- subject players to a 61 percent chance of hitting the wall within four hours. However, bigger bets also make it more likely that normal upswings will help attain win goals. In this instance, chances relative to the 2 percent \$10 bets rise from 63 to 65 percent of winning \$250 before losing \$500, from 44 to 48 percent of earning \$500, and from 26 to 30 percent of walking away with a \$1,000 gain.

You can select a betting level that meets your own personal preferences. In blackjack, 2 percent of a bankroll with a conservative progression will keep you in action 85 percent of the time and offers a good chance at a modest profit. Smaller bets are even less likely to result in a bust-out, and may be desirable if your profit goals are modest. Larger bets may be more to your liking if you're willing to blow your stake in a grab at a bigger prize. Sumner A Ingmark, who never risked ruining rhymes vying for voluminous verses, said it this way:

A gambler who bets small parts of his poke,
Will neither get rich nor go away broke.
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Best of Alan Krigman
Alan Krigman

Alan Krigman was a weekly syndicated newspaper gaming columnist and Editor & Publisher of Winning Ways, a monthly newsletter for casino aficionados. His columns focused on gambling probability and statistics. He passed away in October, 2013.
Alan Krigman
Alan Krigman was a weekly syndicated newspaper gaming columnist and Editor & Publisher of Winning Ways, a monthly newsletter for casino aficionados. His columns focused on gambling probability and statistics. He passed away in October, 2013.