Card Counting Systems Compared
Every counting system does the same job: it gives each card a tag and keeps a running total that tracks whether the remaining cards favor you or the dealer. The systems differ in how many ranks they tag, whether the tags go beyond +1 and -1, and whether you need a true count. Here are the eight most discussed systems side by side, with the published efficiency figures and a drill for each.
At a Glance
| System | Level | Balanced | True count | Difficulty | BC | PE | IC |
|---|---|---|---|---|---|---|---|
| Hi-Lo | 1 | Yes | Yes | Moderate | 0.97 | 0.51 | 0.76 |
| KO (Knock-Out) | 1 | No | No | Easy | 0.98 | 0.55 | 0.78 |
| Hi-Opt I | 1 | Yes | Yes | Moderate | 0.88 | 0.61 | 0.85 |
| Hi-Opt II | 2 | Yes | Yes | Hard | 0.91 | 0.67 | 0.91 |
| Omega II | 2 | Yes | Yes | Hard | 0.92 | 0.67 | 0.85 |
| Zen Count | 2 | Yes | Yes | Hard | 0.96 | 0.63 | 0.85 |
| Red 7 | 1 | No | No | Easy | 0.98 | 0.54 | 0.78 |
| Ace-Five | 1 | Yes | No | Easy | n/a | n/a | n/a |
Efficiency figures are the widely published values from standard comparison tables, such as those by Arnold Snyder, Stanford Wong and the Wizard of Odds. They are not results from our own simulations. We list none for Ace-Five because we could not confirm a standard published value. Hi-Opt I, Hi-Opt II and Omega II figures are for the main count without an ace side count.
Card Tags Side by Side
"10" covers every ten-value card: 10, J, Q and K. The Red 7 count is the only one that looks at suit color, and only for 7s.
What the Efficiency Numbers Mean
- Betting correlation (BC) measures how well the count tracks the player's edge for bet sizing. In shoe games, where most of a counter's edge comes from betting, this is the number that matters most.
- Playing efficiency (PE) measures how well the count guides strategy deviations. It matters more in single- and double-deck games, where each card shifts the right play further.
- Insurance correlation (IC) measures how well the count tracks the density of ten-value cards, which decides whether insurance is worth taking.
No single system leads on all three. Hi-Lo, KO and Red 7 lead on betting; the level-2 counts and Hi-Opt I lead on playing and insurance. Higher numbers only help if you can keep the count just as fast and accurate, which is why most players stay with a level-1 count.
Which System Should You Learn?
KO removes the true count step, so you can bet straight off the running count. Hi-Lo asks for the conversion but is the standard you will see everywhere. Red 7 is a similar easy unbalanced option.
Hi-Lo is the standard for shoe games. Its 0.97 betting correlation is hard to beat, and the Illustrious 18 and most other index charts are built on it.
Whatever you choose, master basic strategy first. A count cannot make up for strategy mistakes on every hand.
Balanced vs Unbalanced Counts
In a balanced count the tags in a full deck add up to 0. Your running count only tells you the edge after you divide it by the decks remaining, which gives the true count.
An unbalanced count tags more cards positive than negative. KO adds +4 per deck and Red 7 adds +2. To compensate, you start from a negative initial running count (4 - 4 × decks for KO, -2 × decks for Red 7), and the running count then does the job of the true count for betting. The trade-off is precision: the running count maps exactly to your edge only at the pivot point.
Practice Any System
We built the speed count drill to handle every system here, including the starting count for KO and Red 7. Pick one and count a shoe:
Frequently Asked Questions
KO or Hi-Lo. KO uses almost the same tags as Hi-Lo but skips the true count conversion, so it is the easiest full count to run at the table. Hi-Lo takes a little more work up front and is the standard that most index charts and books use, so many players start with it directly.
Only once your level-1 count is fast and error-free. Their published playing efficiency is higher than Hi-Lo's, and the gain shows up most in single- and double-deck games. In a 6-deck shoe, betting correlation drives results, and Hi-Lo is already at 0.97.
A balanced count sums to 0 over a full deck, so you divide the running count by the decks remaining to get a true count. An unbalanced count like KO or Red 7 sums to more than 0, and you start from a negative count so that the running count itself can guide your bets.
Yes. The speed count drill has a system selector covering all eight counts on this page, with the correct starting count for KO and Red 7. The true count drill offers the systems that use a true count conversion.
Start Counting
Count a real shoe at your own pace with Hi-Lo or any system above.
Open the Speed Drill