Risk of ruin calculator
Risk of ruin is the probability your bankroll cannot place another bet before the session ends. For flat betting this page solves it exactly — the figures below carry no margin of error, because none exists. Preloaded: a $200 bankroll betting $10 at 49% over 1,000 rounds.
Current game: an abstract betting round — each round wins with probability 49.00%, paying 1 to 1. This is not any real casino game; to try one, pick a preset above, such as baccarat.
Drag this first. It changes the conclusion more than anything else on the page.
Advanced — win chance, payout, push, table limits, seed
Rounds are capped at 100,000.
19.35% of sessions finish ahead — typically by $180.
72.94% run out of bankroll or can no longer place the next required bet, typically down $200.
Across every possible sequence of 1,000 rounds, the expectation is −$108.
Computed exactly — no simulation involved, so there is no margin of error.
Expected versus typical
- Expected ending bankroll
- $92
- Typical ending bankroll
- $0
The average across every simulated session (−$108).
What the middle session experienced (−$200).
These differ because the distribution is lopsided. The average is pulled by outcomes that occur rarely; the median describes the session in the middle.
Outcomes
- Finish ahead
- 19.35%
- Finish behind
- 79.51%
- Bankroll exhausted
- 72.94%
- Strategy could not continue
- 0.00%
Could not place even the minimum bet.
The next required bet exceeded the bankroll or the table maximum, with money still left.
Full detail — percentiles, risk metrics, and the exact figures
Distribution of ending bankroll
- P1
- $0
- P5
- $0
- P25
- $0
- P50
- $0
- P75
- $100
- P95
- $500
- P99
- $740
Risk
- Average largest bet
- $10
- Median maximum drawdown
- $270
- Average longest losing streak
- 8
- Average total wagered
- $5,436
Exact figures
Computed in closed form. No simulation, no margin of error.
- Expected loss per $100 wagered
- $2
- Fair payout for this win chance
- 1.0408 to 1
- Break-even win chance at this payout
- 50.00%
- Chance the next 10 resolved rounds all lose
- 0.12%
- Chance of at least one 10-loss streak within 1,000 rounds
- 44.13%
- Typical longest losing streak
- 9
A different question from the one above, and a much larger number.
95th percentile: 13.
Why a 2% edge ruins so often
At this configuration the ruin probability is 72.94% — computed exactly. A 49% win chance sounds nearly fair, but a $200 bankroll is only 20 bets deep, and ordinary variance crosses 20 bets easily: the typical longest losing streak alone is 9. Ruin risk is a race between a small negative drift and a bankroll's depth; more rounds always favour the drift. Double the bankroll or halve the bet and watch the number fall.