Card Counting Efficiency Calculator

This calculator allows you to determine the Playing Efficiency (PE), Betting Correlation (BC) and Insurance Correlation (IC) of any card counting system.

Just plug in the tag values for each card rank and click Calculate.

For example, for the popular Hi-Lo counting system, you would input the tag value -1 for Ace and Ten, and tag value +1 for 2-6. That shows the Hi-Lo count yields PE=0.5114, BC=0.9682, and IC=0.7601.

Sorry, but the Efficiency Calculator currently requires Flash, and your device doesn’t support that.

We hope to eventually publish a new version that will work on all devices. Subscribe to the mailing list if you want to be notified when it arrives.

  • Playing Efficiency (PE): This is a measure of how effectively a counting system can be used to vary strategy. 0.70 is an approximate cap on the highest possible PE for a single parameter counting system.
  • Betting Correlation (BC): This is a measure of how effective a system is in detecting the player’s advantage based on the remaining cards. It is based on how closely the card counting tags match up with the effect of removal of each card rank. Good BC values can approach 1.00.
  • Insurance Correlation (IC): This is a measure of how well a counting system indicates correct insurance betting decisions.

For much more on the technical details of card counting system efficiencies, see Peter Griffin’s book The Theory of Blackjack: The Compleat Card Counter’s Guide to the Casino Game of 21

Creator of, very few can rival Ken's experience and knowledge of blackjack. His blackjack resume includes winning numerous tournament winnings, making several TV appearances and authoring multiple books on blackjack tournament strategy. Discover more about Ken's background and how he got started here

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I just learned Flash was discontinued due to security issues so this will never work in flash again. Hopefully it can be uploaded in a different format!


I know I’ve used this before and want to use it again! I am trying on my desktop and it still doesn’t want to run.


is it possible that you could send med the formular and prof of the equation behind the calculator. im writting a paper due the 20-12-2019. that would be really helpful.

LV Bear

Sorry, the creator of the calculator has retired and is no longer involved with it.


On Chrome, the browser won’t even give me the option to enable flash on this site until the site attempts to use flash, but the site doesn’t attempt to use flash unless it detects in advance that flash is enabled. So it’s a catch-22.


So where is this wonderful efficiency calculator? I don’t see it anywhere.


Ok, I used it but there is no provision for an Ace side count.


There is no provision for a side count of aces?


@observer just use hi-opt 1. It’s simpler, better, and ignoring aces and deuces helps reduce the correlation with hi-lo.


I’m not sure how much I can trust this calculator because it really ought to give some kind of error message if you give it an unbalanced system. Or at least come with some explanation of what it does for an unbalanced counting vector. This casts doubt on whether I can trust ANY of its results.

What I’m trying to do is find something which has a low correlation with hi-lo (dot product with the vector -1 1 1 1 1 1 0 0 0 -1, but with the last vector component counting 4 times as much since it’s 10 J Q or K, and then divide by the magnitudes of the 2 vectors) so that it’s undetectable to the people behind the eye in the sky the way they’re on the lookout for counters, but has a decent betting correlation. I’m playing around with 1 -1 -1 1 2 0 2 1 -1 -1 tentatively, which has a correlation of 0.3 with hi-low because A, 2 and 3 are reversed. But can I actually TRUST this thing’s results?

Philippe B

Thank you.
I agree. I use ReKO. It was mainly to calculate how weak Speed Count is.

Philippe B

What about Speed Count and OPP and hand substraction ?


How would I calculate a side count of aces effect?


I do not know what other people do, but for a side count I simply insert a letter in front of the running count in my head.

A-20, A-19, A-21 ect.

Strangely it works.

Thank you for the answer I am learning but know so little.
The more I read the less I know.


I am using Knockout counting system with a mild success.
In that book, there is a chart for basic strategy that is a little bit different than what I see everywhere else.
In KO, for a pair of 2 or 3 against the dealers 2 or 3, the decision is to HIT,
But I know that in almost all charts it is advised to split. what should I do here especially if I am playing win no-hole-card rule?


That comment indicates you fundamentally don’t understand how it works to use a counting system to supplement basic strategy decisions. There is no counting system where you just break basic strategy in a consistent way for any reason that is not dependent on the count! For any balanced counting system, when the count is ZERO, then your decision table should match basic strategy exactly. That means you split 2’s and 3’s against a dealer’s 2 or 3, if the count is 0, and that’s why basic strategy says to do that, because on average the count WILL be 0. However, splitting 3’s against a dealer’s 2 IS the one which has its threshold pretty close to a count of 0. For instance, in the classic method known as hilo (I don’t know about knockout), where 2-6 get +1 and A and 10 get -1, the threshold is about -0.3. So you’d hit if the count divided by number of decks left goes under negative one third. If it’s 0, you split. If it’s positive, you split. A pair of 3’s against 3 and the threshold drops to -3.6. Against a 4 and it’s -6.8. A pair of 2’s against 2 and it’s -3.4, a pair of 2’s against 3 and it’s -6.1, a pair of 2 against a 6 and it’s -2.2, against a 3 and it’s -4.7. You can see why basic strategy is what it is because the basic strategy table tells you what you do when the count is 0, or more precisely, what the count would be on average by being dealt that hand. For instance, you double 9 against 2 when the count per remaining deck is more than 1.0, and that also demonstrates why you double on 9 against 2 in a 2-deck game, because just to get a 9 in the first place, you have to have gotten 2 low cards, and the dealer shows a low card, which means the count is 3, so in a 2-deck game, just by dealing a 9 against 2, the truecount is already 1.5, while in a 6-deck game the truecount is 0.5 since it’s a matter of dividing 3 by 2 or by 6, and so in the 2-deck game, basic strategy says double 9 against 2 because 1.5 is more than 1.0, while the 6-deck basic strategy says hit 9 against 2 because 0.5 is less than 1.0. But bottom line, if you’re varying strategy in accordance with ANY counting method, it will always be a function of the count. The decisions that hinge on a threshold that’s very close to 0 are the ones where it also won’t matter much on average if you do one thing or the other if you’re not counting and just using basic strategy. The decision thresholds that are closest to 0 are 16 against 10 hit/stand, 11 against A hit/double and soft 15 against 4 hit/double. Decisions that are kind of close to 0 are 3-3 against 2, soft 19 against 6, soft 18 against 2, and soft 13 against 5. In all of these, it won’t make a huge difference whether you do one action or the other if you’re not counting cards and you can just as well assume the decision thresholds are AT zero as to remember the exact numbers they are (11 against ace, the threshold is -.03, that’s super-super close, that means removing one high-card from a 30-deck shoe makes it no longer worthwhile to double 11 against ace).

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