The Unit System
Most sharp bettors use a unit system to standardize bet sizing. A unit is simply a fixed percentage of your bankroll. Instead of saying "I bet $100 on this game," you say "I bet 1 unit."
This simple shift in thinking is one of the most important habits you can develop as a serious bettor.
Common Unit Sizes
| Unit Size | Risk Level | Best For |
|---|---|---|
| 1% of bankroll | Conservative | New bettors, uncertain edges |
| 2% of bankroll | Moderate | Experienced bettors with validated edges |
| 3-5% of bankroll | Aggressive | Advanced bettors with high-confidence spots only |
Example: If your bankroll is $5,000 and you use 2% units, one unit equals $100.
Why the Unit System Works
The unit system has several powerful advantages:
1. It Scales with Your Bankroll
As you win, your bets grow. As you lose, they shrink. This keeps your risk level constant regardless of whether you're on a hot streak or cold streak.
| Bankroll | 2% Unit |
|---|---|
| $5,000 | $100 |
| $6,000 | $120 |
| $4,000 | $80 |
2. It Makes Performance Tracking Easy
Instead of saying "I'm up $1,500 this month," you say "I'm up 15 units this month." This normalizes results across different bankroll sizes and makes it easier to compare performance over time.
3. It Prevents Emotional Bet Sizing
You can't say "This one feels good, I'll bet more." The system decides for you. This removes emotion from bet sizing decisions—one of the biggest sources of bankroll destruction.
Tip
The unit system is simple, effective, and used by virtually every professional bettor. If you're not using it, start today.
Flat Betting: The Simplest Approach
Flat betting means betting the same amount on every wager, regardless of your edge.
Example: You have a $5,000 bankroll and decide on 2% units ($100). Every bet you make is $100, whether your edge is 2% or 8%.
Advantages of Flat Betting
| Advantage | Why It Matters |
|---|---|
| Simple to implement | No complex calculations required |
| Prevents overconfidence | Stops you from overbetting on "big edges" that might not be as big as you think |
| Psychologically easier | No constant adjustments to bet sizes |
| Protects against edge uncertainty | If you overestimate your edge, you won't over-bet |
When to Use Flat Betting
Flat betting is ideal for:
- New bettors who are still learning to estimate edges
- Bettors with many simultaneous bets where edge estimation is difficult
- Anyone who wants a simple, sustainable system
Note
Flat betting sacrifices some theoretical optimal growth for simplicity and safety. For most recreational and semi-professional bettors, this trade-off is worth it.
Adjusting Your Unit Size
Regardless of whether you use flat betting or a more sophisticated system, you need to periodically adjust your unit size as your bankroll changes.
How Often to Adjust
| Method | Frequency | Best For |
|---|---|---|
| Weekly reset | Every Sunday/Monday | Active bettors (10+ bets/week) |
| Bi-weekly reset | Every other week | Moderate bettors (5-10 bets/week) |
| Monthly reset | First of each month | Casual bettors (under 5 bets/week) |
The Reset Process
- Check your current bankroll (total betting funds available)
- Calculate your new unit size (bankroll × your chosen percentage)
- Round to a practical number (e.g., $87 → $85 or $90)
- Record the change in your tracking spreadsheet
Example Reset:
- Starting bankroll: $5,000 (2% unit = $100)
- After winning month: $6,200 (2% unit = $124 → round to $125)
- After losing month: $4,800 (2% unit = $96 → round to $95)
Warning
Critical: Don't skip the reset when your bankroll drops. Continuing to bet $100 when your bankroll has shrunk to $4,000 means you're now betting 2.5%—increasing your risk of ruin just when you can least afford it.
📝 Exercise
Instructions
Unit Calculation Practice: A bettor started with a $4,000 bankroll using 2% units. After two months, their bankroll is now $5,400. Calculate their unit sizes.
What should their new unit size be after the bankroll grew to $5,400?