A bankroll is money that can lose without changing your life, sized so that a bad month is a number, not a crisis. The rules we use, with the arithmetic behind them.
Money set aside for betting, kept in betting accounts and in a wallet used for nothing else, whose loss you have already accepted. Living money, savings and credit are not a bankroll. The number itself matters less than the rule: stakes are a fraction of it, and the fraction is fixed in advance, not after a loss.
Divide the bankroll into units. One percent is conservative, two percent is standard, five percent is what people do before they learn. With a 1,000 bankroll a unit is 10 or 20; every bet is one, two or at most three units, and the size is decided by confidence, not by the desire to get even.
If stakes are a percentage of the current bankroll, they grow with it and shrink with it, which compounds a winning record and protects a losing one. Recalculate the unit monthly, not daily; daily recalculation turns every good week into larger bets and every bad week into smaller ones, which is the opposite of what a bettor with an edge wants. Our staking guide compares flat, percentage and Kelly stakes.
When the record shows no edge after several hundred bets, the honest conclusion is that the betting is entertainment, and the bankroll should be sized as an entertainment budget: what you would spend on a hobby, no more. There is nothing wrong with that; there is a great deal wrong with pretending otherwise.
Whatever you can lose entirely without consequence; the stake rule matters more than the number.
Only through a percentage plan recalculated monthly, never after a single win.
Monthly, everything above the starting bankroll.