Poker Bankroll Management Calculator

Why bankroll size matters

Poker has variance no other casino game has. Even a strong winner running at 5 big blinds per 100 hands will have 20,000-hand stretches where they break even or lose. Without enough bankroll behind them, a normal downswing wipes out their roll and ends their career before the math catches up. Most players who quit poker did not have a skill problem; they had a bankroll problem.

The standard buy-in multiples

These numbers come from decades of variance simulations and pro consensus, not a single textbook:

PLO needs more because variance is roughly 1.5x to 2x NLHE. Tournaments need by far the most because winning fields of 1,000+ players is rare and even seasoned regs go 100+ tournaments between cashes.

Risk of ruin, and the one formula worth knowing

Bankroll math is built around risk of ruin: the probability your bankroll goes to zero at some point, however long you play. For a cash-game player it has a closed form, and it is short enough to keep in your head:

Risk of ruin = e^(−2 × winrate × bankroll ÷ SD²)

Win rate and standard deviation are both in big blinds per 100 hands, and the bankroll is in big blinds. A typical online 6-max NLHE standard deviation is about 100 BB/100; live full-ring is lower, around 70 to 90; Pot-Limit Omaha runs 130 to 150.

Turn it around to get the bankroll you need for a chosen risk level. For 5%:

Bankroll (in 100 BB buy-ins) = 150 ÷ win rate

That 150 is for a 100 BB/100 standard deviation, the usual online No-Limit Hold’em figure. Pot-Limit Omaha swings about 140, and since the standard deviation is squared in the formula, the constant roughly doubles to 294. Same win rate, twice the bankroll, which is exactly why the PLO row in the table sits so much higher.

A 5 BB/100 Hold’em winner needs about 30 buy-ins to keep risk of ruin under 5%. Drop the win rate to 3 BB/100 and it jumps to 50. At 2 BB/100, which is a perfectly respectable live win rate, it is 75.

That relationship is worth staring at for a moment. Halving your win rate does not add a bit to the requirement, it doubles it. Most of the players who go broke were not unlucky and were not bad; they were small winners playing on a roll sized for a big one.

The formula assumes a fixed stake and no withdrawals, so treat it as a floor rather than a plan.

The hidden cost: moving up

Bankroll rules let you move up. The standard practice is to move up when you have the bankroll for the next level, and move down once you drop below 70% of the requirement at the higher level. Players who refuse to move down on tilt are the most common reason talented players go broke. Stake selection beats hand selection over a career.

Reality check

If you cannot rebuy comfortably, you are underrolled. Money you cannot afford to lose plays differently. You make tighter, more passive decisions and your expected value drops. The bankroll is not just a hedge against variance; it is what lets you make the +EV play every time.

Why tournaments do not use this formula

The risk-of-ruin equation above assumes a roughly normal distribution of results, which cash games have and tournaments emphatically do not. A tournament player’s return is a lottery ticket: they lose small amounts most of the time and occasionally win a hundred buy-ins at once. The distribution is so skewed that the standard-deviation model understates the downswings badly, which is why the tournament buy-in multiples in the table are so much larger than anything the cash formula would suggest. For tournaments, use the multiples and expect them to feel excessive right up until the session where they are not.