Editing Card counting (section)

== Expected profit ==
Historically, blackjack played with a perfect basic strategy offered a house edge of less than 0.5%. As more casinos have switched games to dealer hits soft-17 and blackjack pays 6:5, the average house edge in Nevada has increased to 1%. A typical card counter who ranges bets appropriately in a game with six decks will have an advantage of approximately 1% over the casino. Advantages of up to 2.5% are possible at normal penetrations from counting 6-deck [[Spanish 21]], for the S17 or H17 with redoubling games.<ref>Walker (2008), p. 89</ref> This amount varies based on the counter's skill level, penetration (1 – a fraction of pack cut off), and the betting spread (player's maximum bet divided by minimum bet). The variance in blackjack is high, so generating a sizable profit can take hundreds of hours of play. The deck will only have a positive enough count for the player to raise bets 10%-35% of the time depending on rules, penetration, and strategy.<ref>{{cite web |title=True Count Frequencies |url=https://www.blackjackincolor.com/truecount1.htm |access-date=20 March 2009 |publisher=Blackjackincolor.com |archive-date=5 March 2009 |archive-url=https://web.archive.org/web/20090305134029/http://www.blackjackincolor.com/truecount1.htm |url-status=live }}</ref>

At a table where a player makes a $100 average bet, a 1% advantage means a player will win an average of $1 per round. This translates into an average hourly winning of $50 if the player is dealt 50 hands per hour.

Under one set of circumstances, a player with a 1-15 unit bet spread with only one-deck cut off of a six-deck game will enjoy an advantage of as much as 1.2% with a Standard Deviation of 3.5 on a 2.1 unit average bet.<ref>{{cite web |title=Introduction to the High-Low Card Counting Strategy |url=https://wizardofodds.com/games/blackjack/card-counting/high-low/ |access-date=1 April 2008 |publisher=wizardofodds.com |archive-date=27 December 2011 |archive-url=https://web.archive.org/web/20111227061235/http://wizardofodds.com/games/blackjack/card-counting/high-low/ |url-status=live }}</ref> Therefore, it is highly advisable for counters to set aside a large dedicated bankroll; one popular [[rule of thumb]] dictates a bankroll of 100 times the maximum bet per hand.<ref>Schlesinger (2005), pp. 122-146.</ref><ref>{{cite web |title=Bankrolls, Goals, Risk Data |url=https://www.blackjackincolor.com/blackjackrisk1.htm |access-date=20 March 2009 |publisher=Blackjackincolor.com |archive-date=2 April 2009 |archive-url=https://web.archive.org/web/20090402070438/http://www.blackjackincolor.com/blackjackrisk1.htm |url-status=live }}</ref>

Another aspect of the probability of card counting is that, at higher counts, the player's probability of winning a hand is only slightly changed and still below 50%.<ref>{{cite web |title=Win/Loss/Push Data |url=https://www.blackjackincolor.com/truecount5.htm |access-date=20 March 2009 |publisher=Blackjackincolor.com |archive-date=2 March 2009 |archive-url=https://web.archive.org/web/20090302030832/http://blackjackincolor.com/truecount5.htm |url-status=live }}</ref> The player's edge over the house on such hands does not come from the player's probability of winning the hands. Instead, it comes from the increased probability of blackjacks, increased gain and benefits from doubling, splitting, and surrender, and the insurance side bet, which becomes profitable at high counts.

Many factors affect expected profit, including:
* The overall efficiency of a card counting system at detecting player advantage; affects how often the player will actually play a hand at an advantage per period of time
* The overall efficiency at creating player advantage as a whole; a system may indicate a small advantage when in fact the advantage is much larger – this reduces the overall ROI of the system while in play.
* The rules of the game.
* Penetration will almost directly affect the magnitude of player advantage that is exploitable and the rate that hands are dealt with a player at an advantage.
* The number of players seated at a table will slow the game pace, and reduce the number of hands a player will be able to play in a given time frame.
* Game speed, table with side bets will be dealt at a slower pace than tables without them which will reduce the number of hands dealt over time.
* The use of an automatic shuffle machine or in rare cases, a dealer dedicated solely to shuffling a new shoe while another is in play, will eliminate the need for the dealer to shuffle the shoe prior to dealing a new one, increasing game speed.