Bankroll Management Calculator
Professional bankroll management tools including Kelly Criterion, flat staking calculator, variance analysis, ROI projections, and risk of ruin assessment.
Your total betting bankroll
Your estimated chance of winning this bet
The decimal odds offered by the bookmaker
Kelly Fraction
Click an example to see how different staking strategies affect your bankroll growth. All examples use the Flat Staking calculator with £1000 bankroll and 100 bets.
Low Risk, Steady Growth
1% stake per bet
Strategy:
1% of Bankroll
Risk Level:
Very Low
Minimizes risk of ruin. Best for beginners or those prioritizing capital preservation over aggressive growth.
Moderate Risk/Reward
2% stake per bet
Strategy:
2% of Bankroll
Risk Level:
Moderate
Industry standard for serious bettors. Balances growth potential with reasonable safety. Recommended for most users.
High Risk, High Reward
5% stake per bet
Strategy:
5% of Bankroll
Risk Level:
High
Maximizes growth potential but increases volatility significantly. Only for experienced bettors with high risk tolerance.
What is Bankroll Management?
Bankroll management is the single most important skill for long-term betting success. It's not about picking winners - it's about managing your money so that you can survive variance and capitalize on your edge over time.
Your bankroll is the total amount of money you have dedicated exclusively to betting. This should be money you can afford to lose without affecting your lifestyle. Professional bettors treat their bankroll like a business investment, carefully managing every stake to maximize growth while minimizing risk of ruin.
Why it matters: Even with a proven edge (positive expected value), poor bankroll management can lead to bankruptcy through variance. Conversely, proper bankroll management allows even modest edges to compound into significant long-term profits.
The golden rule: Never risk more than you can afford to lose, and never stake so much that a normal losing streak could wipe out your bankroll.
Understanding Kelly Criterion
The Kelly Criterion is a mathematical formula developed by John Kelly Jr. in 1956 to determine the optimal size of a series of bets. In betting, it calculates exactly how much you should stake to maximize long-term bankroll growth.
The Kelly Formula
Kelly % = (bp - q) / b
- b = decimal odds - 1 (the net odds)
- p = probability of winning (as decimal)
- q = probability of losing (1 - p)
Example: You have a bet with 60% win probability (p = 0.60) at decimal odds of 2.20. The Kelly calculation would be:
- b = 2.20 - 1 = 1.20
- p = 0.60
- q = 1 - 0.60 = 0.40
- Kelly % = (1.20 × 0.60 - 0.40) / 1.20 = 0.267 or 26.7%
However, full Kelly is extremely aggressive. The 26.7% stake would lead to massive swings in your bankroll. This is why most professionals use fractional Kelly.
Quarter Kelly (0.25) - Recommended
Stakes 25% of what full Kelly suggests. Dramatically reduces variance while still allowing steady growth. Ideal for most bettors, especially those with smaller bankrolls or less certainty in their probability estimates.
Half Kelly (0.5) - Balanced
Stakes 50% of full Kelly. Good balance for experienced bettors with proven track records and accurate probability estimates. Still reduces variance significantly compared to full Kelly.
Full Kelly (1.0) - Aggressive
Stakes the full calculated amount. Maximizes long-term growth but causes extreme variance. Only suitable for bettors with very large bankrolls and perfect probability estimates. Not recommended for most bettors.
Staking Strategies Compared
1. Flat Staking (Level Stakes)
Stake the same amount on every bet, typically 1-5% of your starting bankroll. The simplest and most commonly used method.
Pros: Simple, reduces variance, emotionally easier to manage
Cons: Doesn't maximize growth, stakes don't adjust to bankroll changes
Best for: Beginners, recreational bettors, those with inconsistent betting volume
2. Percentage Staking
Stake a fixed percentage of your current bankroll (e.g., 2%). Stakes increase as you win and decrease as you lose.
Pros: Automatically adjusts to bankroll, protects against ruin, allows compounding
Cons: Requires regular recalculation, can be slower to recover from losses
Best for: Intermediate bettors with regular betting activity
3. Kelly Criterion
Stake a percentage based on your edge and the odds. Higher edge = higher stake. Theoretically optimal for growth.
Pros: Maximizes long-term growth, accounts for edge and odds
Cons: Requires accurate probability estimates, high variance with full Kelly
Best for: Experienced bettors with proven edge and accurate models
4. Confidence-Based Staking
Stake different amounts based on confidence: low (1%), medium (2%), high (3%). Subjective assessment of bet quality.
Pros: Allows flexibility, can stake more on best opportunities
Cons: Subjective, prone to overconfidence, harder to track
Best for: Experienced bettors who can accurately assess confidence levels
Understanding Variance & Streaks
Variance is the natural randomness in betting outcomes. Even with a 60% win rate, you won't win exactly 6 out of every 10 bets. Understanding variance helps you:
- Avoid emotional decisions during losing streaks
- Size your bankroll appropriately to survive downswings
- Recognize when poor results are due to variance vs. poor strategy
- Set realistic expectations for short-term results
Expected Losing Streaks
With a 55% win rate over 100 bets, you can mathematically expect:
- 5-6 losses in a row: Very likely (20-30% chance)
- 7-8 losses in a row: Possible (5-10% chance)
- 9-10 losses in a row: Rare but not impossible (<2% chance)
Standard deviation measures how much results vary from the expected average. Higher variance = larger swings = need bigger bankroll to survive.
Use our Variance calculator to see expected streaks for your win rate. This helps set realistic expectations and size your bankroll to withstand normal variance.
Common Bankroll Management Mistakes
1. Staking Too Much Per Bet
Staking more than 5% per bet dramatically increases risk of ruin. Even with an edge, variance can wipe out your bankroll. Professional bettors rarely exceed 2-3% per bet, even on their strongest plays.
2. Chasing Losses
Increasing stakes to recover losses is the fastest path to ruin. Stick to your staking plan regardless of recent results. With percentage staking, your stakes naturally decrease after losses, protecting you from bankruptcy.
3. Not Separating Betting Funds
Your betting bankroll should be completely separate from living expenses. Never bet with money you can't afford to lose. This separation also helps track performance accurately and prevents emotional betting.
4. Ignoring Record Keeping
Without detailed records, you can't know if you're profitable or measure your edge. Track every bet including stake, odds, result, and ROI. This data is essential for improving your strategy and bankroll management.
5. Starting with Insufficient Bankroll
Starting with less than 50 betting units (e.g., £500 for £10 stakes) increases risk of ruin from normal variance. Build a proper bankroll before betting seriously, or reduce your unit size to match your available funds.
Frequently Asked Questions
What is the Kelly Criterion?
The Kelly Criterion is a mathematical formula used to calculate the optimal bet size for a given bet. It balances maximizing growth with minimizing risk of ruin. The formula is: Kelly % = (bp - q) / b, where b is the decimal odds minus 1, p is the win probability, and q is the lose probability (1-p). Most bettors use fractional Kelly (0.25 or 0.5) to reduce variance.
Should I use full Kelly or fractional Kelly?
Most professional bettors recommend fractional Kelly. Quarter Kelly (0.25) is ideal for most bettors as it significantly reduces variance while still allowing steady growth. Half Kelly (0.5) offers a balance for experienced bettors. Full Kelly (1.0) is very aggressive and can lead to large swings in your bankroll, so it's rarely recommended.
What percentage of my bankroll should I bet?
Professional bettors typically stake 1-2% of their bankroll per bet using flat staking. The Kelly Criterion can recommend higher percentages (up to 5-10%) for strong value bets, but most pros use fractional Kelly to stay conservative. Never stake more than 5% on a single bet unless you have a proven long-term edge.
How do I calculate Kelly Criterion?
To calculate Kelly: 1) Convert your win probability to decimal (e.g., 55% = 0.55), 2) Calculate b = decimal odds - 1, 3) Calculate q = 1 - p, 4) Apply formula: (b×p - q) / b, 5) Multiply result by your bankroll to get stake amount. For safety, multiply by 0.25 (quarter Kelly) instead of using the full result.
What is risk of ruin in betting?
Risk of ruin is the probability of losing your entire bankroll. It depends on your edge (expected value), stake size, and bankroll size. With positive expected value and proper stake sizing (2-5% per bet), risk of ruin should be very low (<1%). Betting too much per bet or having negative expected value dramatically increases your risk of ruin.
Is flat staking better than Kelly?
Both have advantages. Flat staking (betting the same percentage each time) is simpler and reduces variance significantly. Kelly Criterion maximizes long-term growth but requires accurate probability estimates. For beginners, flat staking 1-2% is safer. Experienced bettors with proven edge can use Kelly for optimal growth.
How much bankroll do I need to start betting?
A minimum of £500-£1000 is recommended for serious betting. This allows you to stake 1-2% per bet (£10-20) while maintaining enough betting units to weather variance. Starting with less than £500 makes it difficult to stake appropriately and increases risk of ruin from normal variance.
What is variance in sports betting?
Variance is the natural fluctuation in results that occurs due to randomness. Even with a 60% win rate, you can expect losing streaks of 5-7 bets. Understanding variance helps you avoid emotional decisions and stick to your strategy during inevitable downswings. Proper bankroll management protects you from variance.
Should I increase stakes when winning?
With percentage staking (flat or Kelly), your stakes naturally increase as your bankroll grows. Never increase your stake percentage just because you're winning - this is chasing variance. However, you can recalculate your stake size weekly or monthly as your bankroll changes, adjusting proportionally to maintain your percentage.
How do I recover from a losing streak?
Never chase losses by increasing stake size. Maintain your percentage-based staking system - your stakes will naturally decrease as your bankroll shrinks, protecting you from ruin. Review your betting strategy for errors, but remember that losing streaks happen to everyone due to variance. Trust your process if you have a proven edge.
What is a safe stake size?
For most bettors, 1-2% of bankroll per bet is safe and sustainable. This gives you 50-100 betting units, allowing you to withstand normal variance. Only stake above 2% if you have a proven long-term edge with accurate probability estimates. Professional bettors rarely exceed 5% even on their strongest bets.
Can I use Mr Super Tips probabilities with Kelly?
Yes! Our predictions include win probabilities that you can use directly in the Kelly Criterion calculator. However, remember that Kelly works best when you have an edge over the bookmaker. Compare our probability to the bookmaker's implied odds to confirm positive expected value before using Kelly staking.