Bankroll Simulator
Monte Carlo bankroll simulation for prediction market traders and sports bettors. Simulate hundreds of betting paths to estimate probability of ruin, expected growth, and drawdown risk.
Bankroll Paths
Median
P5/P95
Starting Bankroll
About This Simulator
This Monte Carlo simulator generates hundreds of random bankroll paths using a seeded PRNG for reproducibility. Each bet resolves based on your specified edge over fair odds. Fixed-size bets risk ruin faster but grow linearly; percentage-of-bankroll bets (similar to Kelly sizing) never reach zero but can drawdown severely. Use comparison mode to see how two strategies perform with identical random sequences.
Frequently Asked Questions
What is a Monte Carlo bankroll simulation?
A Monte Carlo simulation generates hundreds or thousands of random betting outcomes based on your edge, odds, and bet sizing strategy. Each "path" shows one possible future for your bankroll. By analyzing many paths together, you get a statistical picture of likely outcomes, worst cases, and probability of going broke.
What does probability of ruin mean?
Probability of ruin is the percentage of simulated paths where your bankroll hit the ruin threshold (typically $0). A 5% ruin probability means that in 5 out of 100 simulations, your bankroll dropped to zero. Lower is better. Even with a positive edge, aggressive bet sizing can produce high ruin probability.
What is the difference between fixed and percentage bet sizing?
Fixed betting risks the same dollar amount on every bet regardless of bankroll size. Percentage betting (like Kelly criterion) risks a fixed percentage of your current bankroll. Fixed betting can lead to ruin if you hit a losing streak. Percentage betting can never reach exactly zero, but can suffer severe drawdowns.
How does edge affect simulation results?
Edge is the percentage by which your true win probability exceeds the implied probability from the odds. A 5% edge at 2.00 decimal odds means you win 55% of the time instead of the implied 50%. Higher edge produces faster bankroll growth but does not eliminate variance risk on any individual sequence of bets.
What does the random seed control?
The seed determines the specific sequence of random numbers used. Same seed produces identical results every time, making comparisons fair. In comparison mode, both strategies use the same seed, so differences in outcomes are entirely due to the strategy parameters, not randomness.
How should I interpret the P5 and P95 lines?
P5 represents the 5th percentile outcome — only 5% of paths end with a lower bankroll. P95 represents the 95th percentile — only 5% of paths end higher. The range between P5 and P95 covers 90% of likely outcomes. A wider gap means higher variance in your strategy.
What is average maximum drawdown?
Maximum drawdown is the largest peak-to-trough decline in a single path, expressed as a percentage. Average max drawdown is the mean of this value across all simulated paths. A 30% average max drawdown means you should expect your bankroll to drop about 30% from its peak at some point during the betting sequence.
How many paths should I simulate?
For quick estimates, 100-200 paths are sufficient. For more precise statistics (especially ruin probability), use 500-1000 paths. The simulation runs in a Web Worker so it will not freeze your browser. More paths produce smoother charts and more reliable percentile estimates.