Ask a professional sports bettor how much they wager on a game and they won't give you a dollar amount. They'll say "one unit" or "two units." That's not jargon for the sake of it — it's the foundation of every sustainable betting strategy.
A unit is a standardized bet size based on your bankroll. At BeginnerBets, we recommend one unit = 1% of your total purse. If your purse is $1,000, one unit is $10. If it's $5,000, one unit is $50.
Why 1% (and not more)
At 1% per bet, you would need to lose 100 consecutive bets to go broke. That doesn't happen if you're betting +EV. Even a bettor who wins just 52% of their bets at -110 odds has virtually zero chance of hitting 100 straight losses.
Compare that to betting 5% per game: now you only need 20 straight losses to go broke. Betting 10%? Ten losses in a row wipes you out. And losing streaks of 10+ bets are not unusual — they're statistically inevitable over a long enough timeline, even for winning bettors.
$1,000 bankroll at 1% units ($10/bet): A 10-game losing streak costs you $100. You still have $900. Uncomfortable, but survivable.
$1,000 bankroll at 5% units ($50/bet): A 10-game losing streak costs you $500. You've lost half your bankroll. Panic sets in. You start chasing.
$1,000 bankroll at 10% units ($100/bet): A 10-game losing streak costs you $1,000. You're broke.
The 1% rule isn't conservative — it's mathematical. It ensures you survive the inevitable losing streaks that every bettor faces, so you're still in the game when your edge plays out over time.
How to set your unit size
Step one: determine your purse (bankroll). This is money set aside specifically for betting — not your rent, not your savings, not your emergency fund. Money you can lose entirely without it changing your life.
Step two: divide by 100. That's your unit.
Step three: every standard bet is exactly one unit. No exceptions. Not "one unit usually but two units when I'm really confident." One unit. Every time.
When to adjust your unit size
Your unit should change as your bankroll changes — but not on every bet. Recalculate your unit size at regular intervals: weekly, biweekly, or monthly. If your $1,000 bankroll grows to $1,200, your unit moves from $10 to $12. If it drops to $800, your unit drops to $8.
This is called proportional betting, and it's how professionals scale. When you're winning, your bets grow with your bankroll. When you're losing, your bets shrink automatically, protecting what's left.
Why units matter more than dollars
Units normalize your results. Saying "I won $500 today" means nothing without context. $500 on a $1,000 bankroll is a 50-unit day — incredible. $500 on a $50,000 bankroll is a 1-unit day — routine.
Tracking in units lets you evaluate your performance honestly. A bettor who's up 30 units over 500 bets is a proven winner, regardless of whether those units are $5 or $500.
The temptation to bet bigger
You'll feel it. A game where you're "sure" and want to bet 3 or 5 units. Resist. Overconfidence is how bankrolls die. Even professional bettors with sophisticated models rarely exceed 2 units on their highest-conviction plays — and many never go above 1.
The Kelly Criterion offers a mathematical framework for variable sizing, but it requires you to accurately estimate your edge on every bet. Most beginners can't do that reliably. Until you have hundreds of tracked bets proving your edge in specific markets, flat 1-unit betting is the safest and smartest approach.
The bottom line: One unit = 1% of your purse. Every bet. No exceptions. It's not exciting. It's not sexy. But it's the reason professional bettors are still betting ten years from now while recreational bettors blow through bankroll after bankroll.
Run the numbers before you bet.
The BeginnerBets +EV Calculator shows you instantly whether a bet is worth placing — based on math, not gut feeling.
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