How to Count Cards: The Hi-Lo System
Big cards left in the shoe favor you; small cards favor the dealer — so track what's been dealt, and bet more when the remainder is rich in tens and aces.
Card counting isn't memorizing every card or being a movie genius. It's keeping one running number in your head — and it's legal. Here's the complete Hi-Lo method, the system used by most professional counters, in four steps.
Step 1 — Learn the card values
| Cards | Count value | Why |
|---|---|---|
| 2, 3, 4, 5, 6 | +1 | Small cards leaving the shoe is good for you |
| 7, 8, 9 | 0 | Roughly neutral |
| 10, J, Q, K, A | −1 | Big cards leaving is bad for you |
Why does a ten-rich shoe favor you? Three reasons: more blackjacks (you get paid 3:2, the dealer doesn't), the dealer busts stiff hands more often (see bust odds), and your doubles connect more often.
Step 2 — Keep the running count
Start at 0 when the shoe is shuffled. Add each card's value as it's revealed — every player's cards, the dealer's, everyone's. A round that shows 4♥, K♠, 9♦, 6♣, A♥ moves the count +1 −1 +0 +1 −1 = 0. That's it. The skill is doing it fast and invisibly, which is purely practice. (Tip: count cards in cancelling pairs — a ten with a five is just zero.)
Step 3 — Convert to the true count
A +6 running count means much more with one deck left than with five. So divide:
true count = running count ÷ decks remaining
Running count +6 with three decks left = true count +2. The true count is the number that actually measures your edge: each true-count point is worth roughly 0.5% of edge, and the house's starting edge is about 0.5% — so around TC +1 the game goes even, and above it you're the favorite.
Step 4 — Bet the count
| True count | What it means | Typical action |
|---|---|---|
| +1 or less | House edge | Bet the minimum |
| +2 | ~Even to small edge | 2–4 units |
| +3 | Solid player edge | 6–8 units · take insurance |
| +4 and up | Strong edge | 8–12 units |
A few famous play deviations come with it: take insurance at TC +3, stand 16 vs 10 at TC 0+, stand 12 vs 3 at TC +2. But understand: none of this works without perfect basic strategy first. Counting adds about 1% of edge; strategy mistakes give back 1% instantly.
The honest fine print
- It's legal, but casinos can back you off. Counting in your head breaks no law; using any device does. Casinos can ask you to leave — bet spreads that scream "counter" get attention.
- The edge is small and slow. ~0.5–1.5% with variance that eats under-funded bankrolls. It's a grind, not a heist.
- Game selection matters. Deep penetration (cut card late in the shoe), 3:2 payout, fewer decks. A 6:5 game is uncountable in practice — the payout tax eats the edge.
Frequently asked questions
Is card counting illegal?
No — thinking is legal everywhere in the US. Casinos can refuse service to suspected counters, and a few jurisdictions let them trespass repeat visitors, but no one goes to jail for keeping a number in their head. Devices and phone apps are a different story: illegal almost everywhere.
Do I need a photographic memory?
Not at all. You track one number, adding +1 or −1. The hard part is speed and doing it while chatting, ordering a drink, and looking bored — which is exactly what practice builds.
Does counting work online?
Not in standard online games — the deck is shuffled every hand. Live-dealer games with real shoes can be counted in principle, but shallow penetration usually kills the edge by design.
What's a realistic win rate?
A well-bankrolled counter playing good games might earn one to two big bets per hour in expectation — say $25–75/hour spreading $25–$300 — with brutal short-term swings. Real, but it's a job, not a jackpot.