Counting System · Level 1

The Hi-Lo Card Counting System

By VectorLogic · Updated October 2026

Hi-Lo is the most widely used card counting system. Low cards count +1, high cards count −1, and you bet off the true count. It is simple enough to keep up under casino pressure and accurate enough for professional play.

Hi-Lo at a glance
Level	1 (every tag is +1, 0 or −1)
Balanced	Yes. A full deck counts to 0
True count needed	Yes
Betting correlation	0.97
Playing efficiency	0.51
Insurance correlation	0.76

Hi-Lo card values

Hi-Lo card tag values
Cards	Tag	Why
2 · 3 · 4 · 5 · 6	+1	Low cards leaving the shoe leave it richer in tens and aces
7 · 8 · 9	0	Neutral: they barely change the player's edge
10 · J · Q · K · A	−1	High cards leaving the shoe hurt the player

How to keep the running count

Start at 0 when the dealer shuffles.
Add the tag of every card you see: yours, other players' and the dealer's.
Carry the total from hand to hand until the next shuffle. That total is the running count.

Here is one round, card by card:

Worked example of a Hi-Lo running count
Card	Tag	Running count
K	−1	−1
5	+1	0
3	+1	+1
9	0	+1
A	−1	0
6	+1	+1
2	+1	+2
Q	−1	+1

Count in pairs

A high card and a low card cancel out. Spotting pairs like K + 5 lets you skip both, which is how experienced counters keep up with a fast dealer.

Converting to the true count

Divide the running count by the decks left in the shoe. A running count of +8 with 4 decks left is a true count of +2. Use the true count calculator to check your conversions.

Betting with Hi-Lo

Raise your bet as the true count rises. This is the default ramp in Counting Edge, with the estimated edge in a 6-deck game (dealer stands on soft 17, 3:2 blackjack, double after split):

Hi-Lo bet ramp and estimated player edge by true count
True count	Bet	Estimated edge
0 or below	1 unit	−0.48%
+1	2 units	+0.02%
+2	4 units	+0.52%
+3	8 units	+1.02%
+4 and above	12 units	+1.52%

Each true count point adds about 0.5% to your edge. Truncate the true count toward zero when sizing bets: +2.9 is still a +2 bet.

Key index plays

Hi-Lo also tells you when to break from basic strategy. These five plays carry most of the value:

Take insurance at true count +3 or higher
Stand on 16 against a 10 at 0 or higher
Stand on 15 against a 10 at +4 or higher
Stand on 12 against a 3 at +2 or higher
Double 11 against an ace at +1 or higher

All 18 are on the Illustrious 18 page, and the basic strategy chart lists the main ones.

Hi-Lo compared with other systems

Hi-Lo compared with other card counting systems
System	Level	True count	Betting corr.
Hi-Lo	1	Yes	0.97
KO	1	No	0.98
Zen Count	2	Yes	0.96
Hi-Opt II	2	Yes	0.91
Wong Halves	3	Yes	0.99

Higher-level systems gain a little accuracy but are harder to keep under pressure. For most players, a Hi-Lo count kept without mistakes beats a Level 2 or 3 count kept with them. Torn between Hi-Lo and KO? See Hi-Lo vs KO.

Where Hi-Lo came from

Harvey Dubner introduced the Hi-Lo count in 1963 as a simpler alternative to Edward Thorp's ten-count. Julian Braun's computer simulations refined it, and Stanford Wong's Professional Blackjack made it the standard system it is today.

Sources

HiLoCountingSystem.kt in the Counting Edge source: Hi-Lo tag values
CountingSystemProfile.kt in the Counting Edge source: bet ramps, starting counts and key counts
CounterStrategyEngine.kt in the Counting Edge source: basic strategy and index plays
Stanford Wong, Professional Blackjack
Don Schlesinger, Blackjack Attack: the Illustrious 18 index plays
How this site's figures are checked: About

Frequently asked questions

Is Hi-Lo good enough for serious players?

Yes. Its betting correlation of 0.97 is close to the best systems, and its simplicity means fewer mistakes at a real table. Many professional players use it for their whole career.

How are aces counted in Hi-Lo?

Aces count −1, the same as tens and face cards. Hi-Lo needs no separate ace side count.

Should I learn Hi-Lo or KO first?

Learn Hi-Lo if you want the most accurate Level 1 count and the most published index plays. Choose KO if dividing by decks remaining slows you down, since KO skips the true count.

What does a full deck count to in Hi-Lo?

Zero. Hi-Lo is balanced: twenty +1 cards and twenty −1 cards cancel out. Counting a whole deck and finishing on 0 is a good accuracy drill.

Practice on Android

Practice Hi-Lo Until It's Automatic

Counting Edge tracks your Hi-Lo running and true count as you tap cards, sizes your bet, and runs timed drills that check your count at the end. Free and open source.

Download APK — Free