This JavaScript calculator is used to determine risk of ruin. One sets the various parameters (win rate and standard deviation) for the game being played and the bankroll that one has (in units). Then simply click on the calculate button. The risk of ruin percentage is determined using George C's formula that was published on p. 8 of his "How to Win $1 Million Playing Casino Blackjack." This formula is also found on p 140 of Don Schlesinger's "Blackjack Attack." The default values are from Table 10.43 on p 218 in "Blackjack Attack" and using a bankroll of 536 units to provide approximately a 5% risk of ruin.

Enter the size of your bankroll (in units):
Enter the Win/100 (from "Blackjack Attack":
Enter the SD/100 (from "Blackjack Attack"):
Your Risk of Ruin % is: