Martingale roulette betting system and calculator

The doubling sequence

With a $1 starting stake, the first six wagers are $1, $2, $4, $8, $16 and $32. Losing all six costs $63. The next requested wager is $64. A win at 1:1 would recover preceding losses plus one starting unit only if that next bet can actually be placed and wins.

Bankroll and maximum bets

After k losses, cumulative loss is b × (2^k − 1), and the next stake is b × 2^k. A finite bankroll or table maximum can interrupt the sequence. A string of small completed cycles does not eliminate the larger possible loss.

The probability of six losses

For a red bet on a standard European wheel, a loss has probability 19/37. Six consecutive losses in the next six spins therefore have probability (19/37)^6, about 1.83%. This is one fixed block, not the chance of ever encountering six losses.

The house edge remains

The next spin keeps the same probability regardless of stake size. Expected loss applies to each amount wagered. Doubling is not a way to turn negative expected value into a guaranteed return.

How fast Martingale stakes grow

A table limit example

Suppose a table allows bets from $5 to $500. Doubling from $5 gives $5, $10, $20, $40, $80, $160 and $320. After those seven losses the player is down $635 and the next Martingale stake would be $640, above the table maximum. On a European red bet, seven losses in a row from the start of a cycle have probability (19/37)^7, about 0.9416%. Each successful cycle wins only $5.