Bankroll Management for Sports Betting: The Kelly Criterion

Proper bankroll management is the difference between long-term profit and going broke. Learn the Kelly Criterion and smart unit sizing.

5 min read

Bankroll Management: The Key to Long-Term Betting Success

Bankroll management is more important than picking winners. Here's how to protect your money.

What is a Bankroll?

Your bankroll is the total amount of money dedicated to sports betting.

Key rules:

  • Separate from rent, bills, savings
  • Money you can afford to lose
  • Never bet with borrowed money
  • Keep it in a separate account

Example:

  • You have $5,000 saved
  • Comfortable losing $500 max
  • Bankroll = $500

The 1-5% Rule

Never bet more than 5% of your bankroll on one bet.

Bankroll1% Unit3% Unit5% Unit
$500$5$15$25
$1,000$10$30$50
$2,500$25$75$125
$5,000$50$150$250

Why this matters:

  • Protects against losing streaks
  • Allows for variance
  • Prevents going broke quickly

Unit Sizing Strategy

Fixed Unit (Beginner-Friendly)

Pick 1 unit size (1-2% of bankroll) and stick to it.

Example:

  • Bankroll: $1,000
  • Unit: $20 (2%)
  • Bet $20 on every game

Pros:

  • Simple
  • Consistent
  • Hard to mess up

Cons:

  • Doesn't account for confidence level
  • Doesn't grow with bankroll

Confidence-Based Units

Adjust bet size based on confidence.

System:

  • High confidence: 3-4 units
  • Medium confidence: 2 units
  • Low confidence: 1 unit

Example:

  • Unit: $10
  • High confidence game: $30-40
  • Medium confidence game: $20
  • Low confidence game: $10

Pros:

  • Maximizes edge on best bets
  • Flexible

Cons:

  • Can overestimate confidence
  • Requires discipline

The Kelly Criterion

Kelly Criterion is a mathematical formula for optimal bet sizing.

The Formula

Kelly % = (BP - Q) / B

Where:

  • B = Decimal odds (e.g., +200 = 3.0)
  • P = Win probability (your edge)
  • Q = Lose probability (1 - P)

Example Calculation

Bet: Cowboys +200 (3.0 decimal odds) Your edge: 40% win probability

Kelly % = (3.0 × 0.4 - 0.6) / 3.0 Kelly % = (1.2 - 0.6) / 3.0 Kelly % = 0.6 / 3.0 = 0.2 = 20%

Bet 20% of bankroll?! That's insane!

Fractional Kelly (Recommended)

Full Kelly is too aggressive. Use 1/4 Kelly or 1/2 Kelly.

1/4 Kelly:

  • 20% Kelly = bet 5% of bankroll
  • Safer, less variance
  • Slower growth

1/2 Kelly:

  • 20% Kelly = bet 10% of bankroll
  • Moderate risk
  • Decent growth

Most pros use 1/4 to 1/2 Kelly.

Dealing With Losing Streaks

Expected Losing Streaks

Even with a 55% win rate:

  • 5-game losing streak: ~35% chance per 100 bets
  • 7-game losing streak: ~15% chance per 100 bets
  • 10-game losing streak: ~4% chance per 100 bets

Takeaway: Losing streaks are normal. Don't panic.

Stop-Loss Limits

Set daily/weekly limits to prevent chasing.

Examples:

  • Max 10% of bankroll lost per week
  • Max 3% of bankroll lost per day
  • After 3 losses, take a break

Never Chase Losses

Chasing = increasing bet size after losses

Why it fails:

  • Emotional, not logical
  • Depletes bankroll faster
  • Leads to tilt

Instead:

  • Stick to your unit size
  • Take a break
  • Review your strategy

Growing Your Bankroll

Adjust Units as Bankroll Grows

Don't keep betting $10 units when you have $5,000.

Strategy:

  • Recalculate units monthly
  • Grow units as bankroll grows
  • Shrink units if bankroll shrinks

Example:

  • Month 1: $1,000 bankroll, $20 units (2%)
  • Month 3: $1,500 bankroll, $30 units (2%)
  • Month 6: $2,000 bankroll, $40 units (2%)

Withdraw Profits Periodically

Don't let your entire bankroll sit in sportsbooks.

Strategy:

  • Withdraw 25-50% of profits monthly
  • Keep bankroll replenished
  • Reduce risk of tilt-betting

Example:

  • Start: $1,000 bankroll
  • End of month: $1,300 bankroll
  • Withdraw: $150 (50% of $300 profit)
  • New bankroll: $1,150

Variance and Bankroll Size

Minimum Bankroll for Strategy

Conservative bettor (1% units):

  • Need 100+ units for safety
  • Example: $1,000 bankroll = $10 units

Aggressive bettor (3-5% units):

  • Need 50+ units
  • Example: $500 bankroll = $10 units

Why:

  • Absorb losing streaks
  • Avoid going broke on variance

Risk of Ruin

Chance of losing your entire bankroll based on edge and bet sizing.

Example:

  • 55% win rate
  • 2% unit size
  • Risk of ruin: <1%

Same edge, 10% unit size:

  • Risk of ruin: ~25%

Takeaway: Smaller units = lower risk of ruin

Advanced Bankroll Strategies

Separate Bankrolls by Sport

Why:

  • Track performance by sport
  • Identify strengths/weaknesses
  • Avoid tilt-betting across sports

Example:

  • $1,000 total
  • $400 NFL
  • $300 NBA
  • $300 MLB

Tiered Bankroll System

Tier 1: Conservative plays (50% of bankroll) Tier 2: Standard plays (40% of bankroll) Tier 3: Speculative plays (10% of bankroll)

Unit sizing:

  • Tier 1: 1% units
  • Tier 2: 2% units
  • Tier 3: 5% units

Bankroll Cycling

Don't bet your entire bankroll at once.

Strategy:

  • Only have 50% in play at any time
  • Keep 50% in reserve
  • Rotate as bets settle

Why:

  • Reduces risk
  • Preserves capital for next week
  • Prevents tilt

Common Bankroll Mistakes

Betting with scared money (can't afford to lose) ❌ No stop-loss limits (betting until broke) ❌ Increasing bets after losses (chasing) ❌ Never adjusting unit size (static units on growing bankroll) ❌ All-in bets (YOLO mentality)

Only bet what you can afford to loseSet daily/weekly stop-lossesStick to unit system during streaksRecalculate units monthlyMax 5% per bet, ideally 1-3%

Bankroll Management Checklist

Before you bet, ask yourself:

  • ✅ Is this bet within my unit size?
  • ✅ Am I at or below my daily loss limit?
  • ✅ Is my bankroll properly funded?
  • ✅ Have I tracked my last 10 bets?
  • ✅ Am I betting emotionally or logically?

If any answer is NO, don't bet.

The Bottom Line

You can be a 60% winner and still go broke with poor bankroll management.

You can be a 52% winner and profit long-term with proper bankroll management.

Key takeaways:

  • Bet 1-5% of bankroll per game
  • Use units, not random amounts
  • Set stop-loss limits
  • Never chase losses
  • Recalculate units monthly
  • Withdraw profits periodically

Bankroll management is boring, but it's the difference between surviving long enough to profit and going broke in month 1.


⚠️ Must be 21+ to gamble. Please gamble responsibly.

If you or someone you know has a gambling problem, call the National Council on Problem Gambling 24/7 at 1-800-GAMBLER (1-800-426-2537) or visit ncpgambling.org.

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