Blackjack Bankroll Calculator for Card Counters
Enter your rules, unit and bet spread. Get win rate, standard deviation, risk of ruin, trip risk, N0 and the Kelly unit, from simulation tables, not rules of thumb.
Hi-Lo · one split, no resplit · insurance at +3 with deviations on · results per hour of rounds observed
Lifetime risk of ruin uses the exponential formula exp(−2·win·bankroll ÷ variance). Trip risk is a reflected-normal approximation. Two hands at one count are treated as independent.
How to read the results
- Win per hour is your expected profit per hour at the table, counting the rounds you sit out.
- Standard deviation per hour is the size of a typical hourly swing. With a 1 to 8 spread it is usually 15 to 30 times the hourly win, which is why counting feels like losing most days.
- Risk of ruin is the chance this bankroll ever hits zero at these bets. Under 5 percent is the usual target for a career roll; 10 to 15 percent is common for a trip roll you can replace.
- N0 is the hours until expected win equals one standard deviation. Below N0, luck dominates.
- Kelly unit is the growth-optimal base bet for this bankroll. Half Kelly is the conservative standard.
When you play for real, Blackjack Logger tracks every session, so you can hold your real results up against these numbers.
The same calculator lives in the app with your own table settings pre-filled.
Bankroll FAQ
What is risk of ruin?
The probability of losing your entire bankroll before the long run rescues you, if you keep playing the same way forever. Most counters aim for 5 percent or less for a career bankroll.
What is N0?
The number of rounds (or hours) until your expected win equals one standard deviation. Past N0 you are more likely than not to be ahead. For a 1 to 8 spread in a 6-deck game it is often several hundred hours.
What is trip risk?
The chance of losing a trip bankroll within a set number of hours. It is higher than lifetime risk of ruin for a short trip because variance dominates early.
Where do the numbers come from?
Frequency of each true count and the advantage at it come from simulations of the exact rule set you pick: decks, penetration, H17 or S17, DAS, late surrender, with or without index plays. More than a billion rounds were simulated to build the tables.
What is the Kelly unit?
The bet size that maximizes long-run bankroll growth for your edge and variance. Most players bet half Kelly or less to smooth the ride.