Losing streak calculator
How likely is a long losing streak? That is really two questions, and mixing them up is the easiest way to misjudge a streak. Both are computed exactly below — no simulation — and update as you change the win chance and round count.
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.
31.13% of sessions finish ahead — typically by $12.
Across every possible sequence of 500 rounds, the expectation is −$10.
Computed exactly — no simulation involved, so there is no margin of error.
Expected versus typical
- Expected ending bankroll
- $990
- Typical ending bankroll
- $990
The average across every simulated session (−$10).
What the middle session experienced (−$10).
These agree closely here, which means the distribution is roughly symmetric.
Outcomes
- Finish ahead
- 31.13%
- Finish behind
- 65.64%
- Bankroll exhausted
- 0.00%
- 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
- $938
- P5
- $954
- P25
- $974
- P50
- $990
- P75
- $1,006
- P95
- $1,026
- P99
- $1,042
Risk
- Average largest bet
- $1
- Median maximum drawdown
- $29
- Average longest losing streak
- 9
- Average total wagered
- $500
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 500 rounds
- 25.08%
- Typical longest losing streak
- 8
A different question from the one above, and a much larger number.
95th percentile: 12.
The two questions
At a 49% win chance, the probability that your next 10 resolved bets all lose is 0.12%. The probability that a 10-loss streak appears somewhere within 500 rounds is 25.08% — far larger, because the streak has hundreds of places to start. Betting systems that "wait for" streaks are priced on the first number but exposed to the second.
Over a 500-round session the typical longest losing streak is 8, and one in twenty sessions sees 12 or more. Streaks this long are not bad luck — they are the ordinary texture of independent events.