Martingale calculator
This is a live simulation of the martingale system: double after every loss, reset after a win. It is preloaded with a $1,000 bankroll, a $1 base bet and a 49% win chance — change anything and every number recomputes.
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.
72.5% of sessions finish ahead — typically by $245.
27.2% run out of bankroll or can no longer place the next required bet, typically down $871.
Across all 50,000 simulated sessions the expectation is −$48.
Estimated from 50,000 simulated sessions and still converging. Figures carry a margin of error that narrows as the run completes.
Expected versus typical
- Expected ending bankroll
- $952
- Typical ending bankroll
- $1,239
The average across every simulated session (−$48).
What the middle session experienced ($239).
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
- 72.5%
- Finish behind
- 27.5%
- Bankroll exhausted
- 0.1%
- Strategy could not continue
- 27.1%
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
- $8
- P5
- $44
- P25
- $502
- P50
- $1,239
- P75
- $1,249
- P95
- $1,261
- P99
- $1,270
Risk
- Average largest bet
- $307
- Median maximum drawdown
- $255
- Average longest losing streak
- 8
- Average total wagered
- $2,244
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.
What actually happens
Over 50,000 simulated sessions of 500 rounds, 72.5% finish ahead — but the average result is still −$48, because 27.2% of sessions end unable to place the next doubled bet, typically down $871. Frequent small wins and rare large losses are the same coin; martingale only chooses which side shows.
What martingale cannot do
Bet sizing cannot move the expectation. At these odds the expected loss is $2 per $100 wagered — computed exactly, no simulation — and it is the same whether you bet flat, double after losses, or follow any other progression. What doubling changes is the shape of the distribution: it trades many small wins for occasional total losses. Drag the rounds slider upward and watch the failure probability climb.