Bankroll / Unit Calculator

A unit is a fixed percentage of your bankroll, and it exists so that bet sizes stay proportional to what you actually have. Talking in units instead of dollars is what makes records comparable: “up twelve units” means the same thing whether the bankroll is $500 or $50,000.

The standard range is one to two percent. That is not arbitrary — it comes from what a normal losing run does to you. At 1%, ten straight losses costs a tenth of the bankroll and you carry on. At 5%, the same run halves you, and climbing back from there needs a far better edge than most people have. Losing runs of ten are not tail events; every bettor has several a season.

The units in the bankroll figure is the one to watch. Fewer than fifty is thin — you are one bad month from being unable to bet your normal size. A hundred or more absorbs the variance that a real edge has to survive to pay off.

Reverse mode answers the more common real question: someone is already betting $100 a game and wants to know what bankroll that implies. At 1% it needs $10,000 behind it. If the actual bankroll is $2,000, they are betting 5% a unit and calling it flat betting — same stake, entirely different risk.

Recalculate periodically rather than continuously. Resizing the unit after every bet makes it a moving target and destroys the point of tracking in units. Monthly, or after a meaningful move in either direction, is the usual convention.

A $10,000 bankroll at 1% gives a $100 unit. Half a unit is $50, two units is $200, five units is $500.

That bankroll holds 100 units. Ten straight losses costs $1,000 and leaves $9,000 — uncomfortable, survivable, and the unit only drops to $90 when you resize.

Now run it at 5%. The unit is $500, the bankroll holds twenty of them, and ten straight losses takes $5,000 — half of everything. To get back to $10,000 from there you need to double, which at any realistic edge takes a long time and might not happen at all.

Same bettor, same picks, same edge. The only difference is unit size, and it is the difference between a bad month and the end of the bankroll.

What percentage should a unit be?

One to two percent for most people. Under 1% if your edge is unproven or your bankroll needs to last; above 3% only if you have a documented, measured edge and can genuinely absorb the swings.

Should I bet more units on stronger plays?

Modestly, if at all. Ratings of one to three units are common and defensible. The risk is that confidence is a poor guide to edge — most bettors’ five-unit plays perform no better than their one-unit plays, and sizing on feel amplifies whatever bias produced it. The Kelly calculator sizes on edge instead.

How often should I resize my unit?

Periodically — monthly, or after a meaningful move. Resizing after every bet makes the unit a moving target and destroys its value as a unit of account; never resizing means a shrinking bankroll is betting an ever-larger share of itself.

What counts as my bankroll?

Money set aside for betting that you can lose entirely without it affecting anything else. Not your savings, not money you might need. If losing it would change your decisions, it is not bankroll.

Is flat betting better than varying stakes?

For most people, yes. Flat betting removes the largest source of self-inflicted damage — sizing up on the bets you feel strongest about, which is exactly where overconfidence lives. Varying stakes is only better when the variation tracks measured edge rather than confidence.

• Bankroll Management: Units, Flat Betting and RuinA real edge with the wrong stake size still goes broke. What a unit is, why flat betting wins, and how deep a normal losing run goes.11 min read

• Profit / Units CalculatorUnits won or lost, converted into money and a bankroll return.
• Kelly Criterion CalculatorThe stake your edge justifies, at full Kelly or a safer fraction of it.
• Risk of RuinThe chance a bankroll does not survive the variance.
• Bankroll SimulatorTen thousand seasons of the same edge, and where they end up.