Card counting systems
A counting system gives each card rank a tag value. The player adds the tags of the cards already dealt. The running count then describes the cards left in the shoe.
Systems compared
The table states the level of each system and the two efficiency figures for it.
| System | Level | Balanced | Ace neutral | Betting correlation | Playing efficiency |
|---|---|---|---|---|---|
| Hi-Lo | 1 | Yes | No | 0.97 | 0.51 |
| Knock-Out | 1 | No | No | 0.98 | 0.55 |
| Omega II | 2 | Yes | Yes | 0.92 | 0.67 |
What the two figures mean
Betting correlation predicts how well the count sizes a bet.
Playing efficiency predicts how well the count changes a play.
A level two system carries more tag values than a level one system.
An unbalanced system starts the count away from zero for each deck count.
Both efficiency figures come from the publisher named in the table caption.
Legality and practice
Card counting is not illegal in the markets we cover.
A venue can refuse service to a player the venue believes counts.
The simulator on this site reshuffles after every hand.
No count survives a reshuffle, so the simulator cannot train a count.
The counting drill in the trainer is the surface that teaches counting.
Open the counting drill in the trainer
Where these figures come from
Every tag value and every figure on this page traces to a source below.
- https://wizardofodds.com/games/blackjack/card-counting/high-low/
- https://www.qfit.com/card-counting.htm
- https://www.qfit.com/cardcounting/Omega-II/
- http://www.deepnettech.com/OmegaII.pdf
- https://www.blackjackhero.com/blackjack/strategy/card-counting/omega-ii/
- https://www.lasvegasadvisor.com/shop/wp-content/uploads/2017/06/KOBJ-Sample.pdf
- https://www.blackjackreview.com/wp/2025/09/14/ko-with-table-of-critical-running-counts-2/