I know that people have different metrics for different stakes. From what I read it's usually 200x the big blind of the stakes you're playing at. I'm about to start saving again to build a Proper bankroll and starting using BR Management this time around to avoid going bust. So what is the proper bankroll rule to follow when saving/starting a bankroll?
First off, 200 times the big blind is NEVER* enough. That's two buy-ins. If that were your bankroll, you would go broke, even if you were the best poker player on the planet.
SoboLAN's answer was a great one for MTTs. For SNGs, you can probably start out a bit lower than that - around 60% of his recommendation should be ok if you are playing a relatively low number of games simultaneously and/or you are playing regular-speed games. If you are multi-tabling turbo SNGs, you should probably stick with the values he gave.
For cash games, Toby's answer listed a lot of the factors that you should consider. I'll add to that with some specific recommendations. If you're willing to deposit more money into your BR should you encounter a bad run AND/OR you are willing to move down in stakes, then you should be ok to use 25 buy-in base. As you move up in stakes, your edge on the field shrinks while the money becomes harder to replace and more meaningful. That should, generally, cause you to require a larger bankroll. In mid-stakes, a 40 buy-in minimum is pretty reasonable. Some prefer more. Then as you move into high-stakes, you should increase further. I have pretty limited experience with any stakes that would be called "high" (e.g. over $1k buy-in cash games), but when I was flirting with those games, I wanted at least 50 buy-ins.
*As another posted noted in the comments on the question, the one exception to my statement that 200 times the big blind is never enough is if you are playing fixed-limit games. In limit, it is proper to use a multiple of the blind to determine your BR requirements, however big bets are a more common measure than big blinds. Typically a big bet (e.g. the bet size on the turn and river of limit games) is double the big blind and 200x the big bet is probably fine for starting out. As you progress to higher stakes, you'll want to move to 300x the big bet or more.
Since I rarely play cash games, I'll only talk about tournaments.
When it comes to tournaments, the bankroll you choose must depend on both your skill level and on your financial possibilies. You may be a millionare, but starting to play tournaments that have $5000 as buy-in is definitely not a good idea.
Basically, my rule is at least 60 buy-ins for tournaments. For example, if you have a bankroll of $100, then entering tournaments with $5 buy-in is not so good, but entering the ones with $1 is good.
If you start to increase your bankroll to a level where entering more expensive tournaments may be possible, then you can start playing such tournaments a little earlier. Maybe just to get a feeling about them. This bankroll management rule is meant to be bent (but not broken). Once you get your bankroll to about 150 buy-ins, you can take a step up the ladder more permanently.
The biggest problem when it comes to this is that poker players have a big ego and forget that you can't just climb up the ladder. Sometimes you have to climb DOWN. Some situations may come when you're getting low on cash and entering the usual tournaments doesn't make much sense financially. To use the previous example: if you get as low as $40, then entering $1 tournaments is a little too much, you may have to go down to $0.50 ones.
Most poker player's take this as taking a step backwards in their carrer. And they hate it. And they avoid it. And they get broke because of it. THEY'RE WRONG. This is not going backwards, this is simply adapting to the new conditions. When sitting at a table, you always adapt your play, taking into account dozens of factors (table image, stack sizes, field size etc. etc. etc.). You learn to be adaptable in your play, so why not when it comes to your bankroll ?
Bottom line: Those numbers that I gave you (60 and 150) are just guidelines. Make your own (reasonable) rules and stick to them. They're sacred rules. Bend them when you're at one of their edges, but never break them. If you do break them, you'll regret it. I PROMISE YOU.
Deciding how comfortable you are with going bust (a.k.a. Risk of Ruin or RoR), is arguably the most important issue regarding how you personally manage your bankroll.
Issues like the depth of your bankroll, how you handle variance, the type of games you play, and potentially your drawdown (if you're living off the income from playing) are part of understanding RoR.
Check out this answer to find some useful links to online tools that will help you.
I think it was Mason Malmouth who wrote an article about "The Silly Subject of Bankroll", I paraphrase.
In the old days when the game of choice was big blind Texas Hold'em for professional players the benchmark was 300 big blinds was a adequate bankroll that would allow a player a 95% margin for not going broke with standard deviation. (Big Blind hold'em is games like 10/20, 20/40 where the bets are structured and the big blind is the size of the first two rounds of betting.)
This three hundred big blind thing was figured out using a standard deviation formula by someone writing a book. I think it was Mason or David Sklansky. What makes it so silly is not that it is bad math, it is just bad math for you and me. It does not account for variables outside of random distribution. The flaw being that when someone saved up their 6000 bankroll and headed to Las Vegas to become a professional poker player they went broke 95% of the time thus heading home with their tail between their legs.
Was not S&M's fault, I believe they said it was a guide line, and they themselves started saying the subject of bankroll was silly.
It does not take into account so many other things that are relevant and important to your bankroll. One of those things is perhaps the cost of living. Another one of those things is that minimum bankroll is typically calculated on the assumption that the player is playing optimal and making their two big blinds an hour. Things like what kind of tipper he is, how much rake he is playing and how many drinks he buys, don't really fit in the equation and yet they are bankroll negative factors.
I don't know why they did not try to figure these things out, it might be that the answer was different for everyone or perhaps they did not want to discourage people from taking a shot at professional poker. Maybe players feared that people would figure out that they could make a much better living using a $6000 bankroll to buy a hotdog cart.
Few players have successfully figured out bankroll requirements. Few player ever will. I say this because in my casual observation of poker players, they almost all go broke at one time or the other. The ones that do not, have seemed to have something besides just poker to keep them going. Chris Moneymaker might be a good example of this. I am sure that with out all the endorsement funds that he has had coming in over the years, and perhaps his wisdom of investing in other things besides himself in a poker seat, he would more likely then not have been busted. Jonny Chan went broke after his back to back wins, as other if not most of the WSOP main event winners have.
It has dawned on me over the years of watching many of my bankrolls come and go, and many others bankrolls come and go, that bankroll is really a silly little subject and that the answer is not really build a bankroll, stay within it and you will be in chips forever. You more likely then not will lose your bankroll and be sleeping in your car for to many nights.
When you consider your bankroll I think the question is really more about how much you can play with what you got, and how easily can you replace what you have. If your talking about a bank roll to play online in with micro limits then bankroll question is do I have an extra twenty to screw around with, and will I care if I loose it?
If your on the other extreme, you play high limits, your main income is going to be from poker, or you think you are a great player and your leaving the wife and quitting the job to become a fulltime poker player you have a whole new set of problems, and if you do not address them you will be going home.
I have only met a few successful poke players in the sense of bankroll. I will tell you about one, he is a famous poker player with a dad that is even a bigger name in the poker world. The first time I saw this guy who was just a kid that was playing 3/6 limit. He moved up and has never been busted out. But build a bank roll is not all he did, he built a portfolio. Now I am sure that his BR has fluctuated, I would even be willing to bet he has lost a bankroll or two. But his portfolio is huge, many times bigger then any bankroll he would ever need. He built his portfolio playing poker. Smart kid. Only guy I really heard of that grinded his way to the top. I think has formula is correct and perhaps the best to follow. Build your bankroll from your winnings, invest your winning, when your investments can sustain you, become a poker professional, repeat get really rich and secure.
Bankroll is really silly.