How many units should you bet? Unit sizing explained

Ask ten bettors how they size bets and you'll get ten answers, most of them some version of "depends how I feel about it." That's the problem. Sizing by feel means your biggest bets tend to land right when you're most emotionally invested, which is not the same as when you're most right.

Units fix that by making size a rule instead of a mood.

What a unit is

A unit is a set percentage of your bankroll. With a $1,000 bankroll and a 1% unit, 1u = $10. Bet 1u on a normal play, 0.5u on a lean, 2u on your strongest. Now every result is "+3.2 units" instead of a dollar figure that means different things at different bankroll sizes.

Why smaller units win

Losing streaks are not rare; they're guaranteed. What matters is how deep one cuts. Here's a five-bet losing streak at two unit sizes:

• 1% per bet: bankroll after five losses = 0.99⁵ = 95.1%. You're down 4.9%.
• 10% per bet: bankroll after five losses = 0.90⁵ = 59.0%. You're down 41%.

Setting your unit

• Start at 1%. It's boring on purpose. 2% is a reasonable ceiling for most people.
• Use money you can afford to lose. Your bankroll is a separate pot, not rent money.
• Re-set on a schedule. Recalculate the unit monthly or at set milestones instead of after every bet. Otherwise you're constantly changing your sizing mid-streak.

Sizing up and down

A narrow range works: 0.5u for a lean, 1u standard, up to 2u for your best. The mistake is stretching that to 5u "because I'm sure." If you're sure, check the math: edge = your win % − break-even %. A bigger edge justifies a bigger bet, but only in proportion. Kelly-style sizing formalizes this, and most people use a fraction of it (like quarter Kelly) because their edge estimate is never perfectly accurate.

Three habits that protect the bankroll

• Never chase. Don't raise your unit to win back a loss. That's the fastest route to the 41% scenario above.
• Cap daily exposure. For example, no more than 5 units at risk in a day.
• Track every bet. You can't improve what you don't measure, and sizing errors only show up in the log.

Quick answers