Poker bankroll management, without the guesswork

Buy-ins, not money

Your bankroll size in buy-ins, set against your win rate and standard deviation, determines what you can safely play. Thinner edges and bigger swings demand more buy-ins for the same low risk of ruin.

Moving up and down on rules

Move up only when both the buy-in count and a proven win rate clear the bar, not on a hot streak. Move down on a pre-set rule when the roll dips. The discipline is in deciding before emotion does.

Surviving variance

You cannot remove variance, only outlast it. Enough buy-ins, stakes you are rolled for, and a stop-loss to protect the A-game keep you in action through the downswings that the maths guarantees.

A practical bankroll rule set

Good poker bankroll management is not a single magic buy-in number. It is a rule set you can follow when the latest session is trying to talk you out of discipline. Start by separating the poker bankroll from living money. Then size the stake in buy-ins, not in cash, because a GBP 1,000 bankroll means something very different at 1/2 than at 2/5. Finally, write the move-up, shot-taking and move-down rules before you need them.

For live cash, a conservative starting frame is simple. Keep the main stake deep enough that a normal downswing does not threaten the roll. Take shots only with a fixed budget and a clear stop point. Move down automatically when the buy-in count falls below the rule, even if the last session felt unlucky. The rule should be boring enough to follow while tilted. If it needs a fresh argument every time, it is not a bankroll rule, it is a hope.

The right buy-in count depends on win rate, standard deviation, game type and life pressure. A player with no outside poker income, a thin edge and high-variance games needs a deeper roll than a recreational player with stable income and a small capped risk. Overshove does not pretend the same answer fits both. It keeps the session record, cost fields and variance context together so the bankroll decision can use the facts you actually produced.

Risk of ruin, and where the 5 percent rule comes from

Risk of ruin is the probability that you lose your whole bankroll before your edge plays out. It is the number the buy-in count is really trying to control, and it has a closed form for a fixed win rate and standard deviation:

risk of ruin = e^(-2 × W × B / S²)

W is your win rate in BB/100, S is your standard deviation in BB/100, and B is your bankroll in big blinds. Rearranged for the bankroll that hits a chosen risk, it becomes:

bankroll in big blinds = -S² × ln(risk) / (2 × W)

The commonly quoted 5 percent rule is just that formula with risk set to 0.05. Because the natural log of 0.05 is about -2.996, the whole thing collapses to roughly three times S squared, divided by twice your win rate.

Worked through: a 4 BB/100 winner with a 90 BB/100 standard deviation needs about 3,033 big blinds, near enough 30 buy-ins at 100 BB each, to hold risk of ruin at 5 percent. Drop to 20 buy-ins and the same player's risk of ruin rises to about 14 percent. Halve the edge to 2 BB/100 and raise the standard deviation to 100, and the 5 percent bankroll jumps to roughly 75 buy-ins. Push for 1 percent instead of 5 at the original numbers and it is about 47 buy-ins.

Two honest caveats. The formula assumes a constant edge and normal swings, which real poker only approximates, so treat the output as a sizing guide rather than a guarantee. And it says nothing about whether your measured win rate is real: a win rate from too small a sample makes the whole calculation confident nonsense, which is why sample size matters before bankroll maths does.

The move-up test

A move-up decision should clear three tests. First, the bankroll test: after buying into the next stake, the remaining roll still leaves enough buy-ins to survive a normal bad run. Second, the skill test: the lower stake sample shows a real edge, not just a short heater. Third, the behaviour test: the bigger pots do not change the decisions so much that the old win rate becomes irrelevant. Missing any one of those tests turns a move-up into a gamble.

Shot-taking is different from permanently moving up. A shot is a budgeted experiment. You decide how many buy-ins can be risked, what result ends the shot, and what evidence would justify another one. The cleanest rule is written before the first hand: if the shot loses two buy-ins, return to the main stake; if the game is excellent and the roll is still within the rule, continue; if the bigger game makes you passive or reckless, stop even if the result is positive.

Moving down is the part players avoid, but it is the move that keeps a bankroll alive. Dropping stakes after a rule is not failure. It is the system doing what it was built to do. The player who moves down on time gets to rebuild from a controlled spot. The player who waits until pride is satisfied often rebuilds from zero.