Bankroll management is one of the most critical skills needed by professional gamblers if they hope to be successful at their jobs. Without successful bankroll management, a player is likely to go broke by wagering too much at the wrong times, or not properly keeping records of their play. Without bankroll management, all the other skills and knowledge a player has are mostly useless in the long run.
What Bankroll Management Doesn’t Do
Off the bat, it’s important to realize what bankroll management cannot help you with so that there’s no confusion. Even the best bankroll management strategy won’t help you if you are playing at a disadvantage since you’ll lose your money sooner or later.
This is critical to realize, because many gambling scams are based on the idea that bankroll management systems can somehow make you money on a game with a house edge, such as playing craps (or even blackjack without using any sort of advantage play). Be wary of any such claims; bankroll management is important because it stops you from making mistakes with your money, not because it can give you an increased advantage over the house.
Why Bankroll Management is Important
Bankroll management is critical because of the swings – known as variance – that even winning players will have when gambling. Blackjack, for instance, is a high-variance game that will feature big winning streaks and huge short-term losses, whether you play at an advantage or simply play for fun. Given this, it’s quite possible to see huge losses pile up quickly, and a player who is not carefully managing their money can go broke faster than you might imagine.
In order to be a successful professional gambler, a player must keep their risk of ruin (the likelihood that their bankroll will ever be completely wiped out) very low. It’s impossible to ever have a 0% risk of ruin, but a sufficiently careful strategy can get close.
That said, having the lowest possible risk of ruin isn’t the best idea either. If a bankroll management strategy is too conservative, the bankroll will grow very slowly, making it more difficult for the player to progress to playing at higher stakes and being able to support themselves through their winnings. The best bankroll management strategies combine a low risk of ruin with a high potential for bankroll growth. Finding and maintaining this balance is the essence of good bankroll management.
The Kelly Criterion
One such strategy that attempts to grow bankrolls as quickly as safely possible is the Kelly criterion. The Kelong-termrion is designed to outperform any other gambling strategy in terms of long term returns, provided that all bets are made with the same payouts and same probability of winning and losing each time.
In our article on Betting Strategies, we laid out the formula for sizing Kelly bets, which looks like this:
f = (bp-q)/b
f = the fraction of your bankroll you should wager;
b = the odds you are receiving on each bet, expressed in terms of “b to 1;”
p = the probability of winning;
q = the probability of losing.
However, since blackjack has many different types of bets and payouts, we need to make some simplifying assumptions. One popular way to do this is to approximate the formula is as follows:
f = a/v
a = the player advantage;
v = the game’s variance, which is the standard deviation of the game squared.
Let’s look at an example from blackjack. According to The Wizard of Odds, the standard deviation of blackjack is about 1.15 bets; squaring that figure gives us a variance of 1.3225. If a player believes they have a 2% advantage over the house (thanks to card counting or other advantage plays, the simplified Kelly criterion would tell them to size their bets as follows;
0.02/1.3225 = .015
This number is expressed as a percentage of the player’s total bankroll – in this case, 1.5%. If a player starts with a $10,000 bankroll, this would suggest betting $150 per hand.
The Kelly criterion is a very aggressive bankroll management strategy, which makes some players very nervous when using it. It is designed to maximize bankroll growth, and while the player is unlikely to actually go broke when using it (if the player begins losing, they should start betting less to reflect their now smaller bankroll), large losses are very possible.
Because of this, many players choose to use a more conservative approach, such as the “half Kelly.” The half Kelly is just what it sounds like; you simply calculate the Kelly bet size, and then halve it. It’s important to note that while this does reduce the risk to your bankroll, it reduces your potential gains even more severely, so there is a cost for being more conservative.
Regardless of the specific bankroll management system you choose to use, it should be obvious that your bets should be rather low compared to the size of your bankroll. Betting too much on individual hands can quickly get a professional gambler into a lot of trouble.
Other Bankroll Management Tips
- Make sure to separate your bankroll from the money you use for living expenses. You should not be living off your bankroll, nor should you ever use money from outside your bankroll for gambling (at least, not your professional gambling). You can pay yourself on a regular basis out of your bankroll, but that should be the only time you take money out of your bankroll for other uses, except in the case of emergencies.
- If your emotions tend to get the better of you at times, it may be wise to set a stop-loss limit. This may help prevent you from blowing your money when you’re having a bad day and not thinking straight.