The table the system is made of
| Rank removed | House edge moves | Who that helps | Hi-Lo says |
|---|---|---|---|
| Ace | +0.5785 pp | the house | -1 |
| 2 | -0.3888 pp | the player | +1 |
| 3 | -0.4634 pp | the player | +1 |
| 4 | -0.6272 pp | the player | +1 |
| 5 | -0.8133 pp | the player | +1 |
| 6 | -0.4580 pp | the player | +1 |
| 7 | -0.2913 pp | the player | 0 |
| 8 | +0.0277 pp | the house | 0 |
| 9 | +0.2029 pp | the house | 0 |
| Ten, Jack, Queen or King | +0.4957 pp | the house | -1 |
Read one row. Take a five out of the deck and the house edge falls by 0.8133 percentage points, so the player is better off. A counter therefore wants fives gone, and the system records that as +1. Take an ace out and the edge rises by 0.5785 points, so the player is worse off, and the system records −1. That is the whole idea. Everything else is bookkeeping.
Four things the table says that the usual explanation does not
The five is the most valuable card in the deck. At 0.8133 points it beats every other low card, and it is the reason a five-count was the earliest system anyone published. Hi-Lo flattens it to +1 alongside the 2, which is worth less than half as much.
The ace is third, not first. At 0.5785 points it comes after the five and the four and just ahead of a ten worth 0.4957, and Hi-Lo scores the ace and the ten alike, −1. The order is the one Wizard of Odds publishes for a six-deck shoe: 5, 4, ace, ten, 3, 6, 2, 7, 9, 8.
The eight is the real neutral, not the middle of 7-8-9. At 0.0277 points it is as close to nothing as any rank gets.
And the nine leans the wrong way. Removing a nine raises the house edge, by 0.2029 points. Hi-Lo calls it zero for simplicity; systems that carry more values, like Hi-Opt II and Omega II, give the nine a number for this reason.
What this does not tell you
This is the foundation, not a system to play. It says which cards a counter wants gone and how much each one is worth. It does not tell you how to convert a running count into a true count, what bet spread to use, how deeply a shoe must be dealt for any of it to pay, or how to avoid being asked to leave. Those are separate problems and this page does not pretend to solve them.
It is also worth being blunt about the size of the prize. Under a standard rule set this site computes at 0.5117%, a counter is trying to turn a small negative into a small positive. Sit at a 6:5 table, which costs 1.35 percentage points on its own, and no count available recovers it. The rules you choose before you sit down decide more than the arithmetic you do afterwards.
Is it legal
Yes. Counting cards is thinking about information available to everyone at the table, and no jurisdiction in our law table makes it a crime. Casinos are private businesses and can refuse service, which people often confuse for illegality. Being asked to leave is not the same as breaking a law.
Frequently Asked Questions
- Why is a 2 worth +1 and a 9 worth 0?
- Because removing a 2 lowers the house edge by 0.3888 percentage points while removing a 9 raises it by 0.2029. The counter wants low cards gone and high cards left, and the sign of the effect is where the value comes from.
- Which single card matters most?
- The five, at 0.8133 percentage points, then the four at 0.6272. The ace comes third at 0.5785, just ahead of the ten at 0.4957, and Hi-Lo scores the two alike, as -1.
- Which card is the true neutral?
- The 8, at +0.0277 percentage points, which is as close to nothing as any rank gets. The 9 leans towards the house, which is why some systems give it a value where Hi-Lo does not.
- Is card counting illegal?
- No. It is thinking, and no jurisdiction on this site's law table criminalises it. Casinos are private businesses and may refuse service, which is a different thing from a law being broken.
- Does counting still work?
- The arithmetic on this page does not expire. What has changed is the game around it: continuous shufflers, worse penetration and 6:5 blackjack, which costs 1.35 percentage points on its own and swamps what a count can recover.
The table above is produced by
counting_math.py at build time. It replaces the engine's
rank distribution with a single deck missing one card, reprices the whole
game with blackjack_math.py, and takes the difference. The
engine draws independently from a fixed distribution rather than
modelling a shoe as it depletes, so the magnitudes run larger than a full
finite-deck analysis gives; the signs and the ordering, which are what a
counting system is made of, are what this is for. The build checks the
computed signs against Hi-Lo and the order against
Wizard
of Odds' six-deck effects of removal, and refuses to write this page if
either disagrees. Last computed October 2026.
Corrected on 17 October 2026: the engine priced the dealer's natural from a full deck even with a card removed, which made the ace look like the largest effect (1.0205 points) and put the eight on the player's side. Repriced from the depleted deck, the ace is third, and every value on this page moved.