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Test Credit Card Numbers With Luhn Credit Card Validation

Published 7/11/08 (Modified 6/17/11)
By MoneyBlueBook

What Do the Credit Card Numbers Mean, and How Are Valid Credit Card Accounts Generated?

Have you ever wondered how credit card companies generate all those account numbers that appear on the face of the credit cards you carry around in your wallet? At first glance the numbers, while neatly arranged, appear to be completely random. But would it surprise you to know that there is indeed meaning and actual mathematical methodology to the way the numbers are sequenced? The process of generating real credit card numbers and validating them based on a proven mathematical formula is not only intriguing on an intellectual level and a hacker's dream, the carefully calculated way the numbers are ordered is actually quite beautiful and elegant when you come to understand how it works.

Before I get down to explaining the anatomy of credit card numbers and discussing how credit card numbers are generated, I think it's prudent to remind everyone the intent of this article. The goal of this blog post is not to encourage or get people thinking about how to go out and create fake credit card numbers on their own for improper means. The purpose is to shed some light on the science behind the mathematical sequencing technology of valid credit card numbers and offer some insight into something that many of us frequently see and use everyday, but oftentimes don't pay much attention to.

Please take in the information provided for purely academic and entertainment reasons. I'm not trying to encourage anyone to create fake credit card numbers and get themselves in trouble with the law. For anyone even thinking about engaging in fake credit card number hacking, keep this in mind - using mathematically generated credit card numbers to purchase products over the Internet or in real life is not only unethical and highly illegal, it's also not yet technologically possible (yet), based on the sheer probability of long shot odds of 1 in trillions. After reading everything I'm about to say carefully, you'll also realize that there is no realistic way to generate actual working credit card numbers that could be used for anything but entertainment reasons. The math and science behind generating authentic credit card numbers are only good for validation purposes and not sufficient for creating workable numbers as several highly encrypted numerical components are still needed. So, with that obligatory disclaimer out of the way, here is a short guide on how anyone can generate and verify the authenticity of any credit card number.

Basic Background About Credit Card Numbers and How They Work

Rather than ask you to take out a credit card out of your wallet to examine it, I've provided a picture of a prototypical card - in this case, it's a Visa credit card. While different card types offer different lengths of numerical digits, most major credit card issuers popular in the United States have 16 primary numbers on the front face of the card. Visa, MasterCard, and Discover cards all have 16 digits. American Express is the only major credit card issuer in the U.S. with one less number - at 15 digits. Regardless of the length of numbers, their numerical sequencing is still guided by the same Luhn validation formula, the mathematical check sum equation that makes all valid credit card numbers error free.

As you can see from the picture of the Visa card above, the very first 6 credit card number sequence is known as the issuer identification number (IIN) or bank identification number (BIN). These first 6 numerical digits denote the credit card network and the banking institution the card is a member of. The issuer identifier number also incorporates the card type's special identifying numerical prefix.

  • All typical 16 digit Visa account credit card numbers start with a prefix of 4.
  • All 16 digit MasterCard account numbers start with a prefix of 5.
  • All 16 digit Discover account numbers start with a prefix of 6011.
  • All 15 digit American Express credit card numbers start with a prefix of 37.

There is less randomization during this initial set of 6 digits as the numbers are determined purely by the card issuing source. Validation systems that want to go the extra mile in verifying authenticity oftentimes scan this first numerical sequence to match the known bank and issuing location of the card with the provided customer billing address for further validation accuracy.

The lone digit at the very right end of the complete 15 or 16 digit credit card number sequence is known as the "check digit", which often is the final number that is computer generated to satisfy the mathematical formulations of the Luhn check sum process. Meanwhile, in between the first 6 digits and the last single check digit is the actual personalized account number - the 8 or 9 digit sequence given by the card issuer. For more basic background information about credit card numbers, check out this credit card features brochure for more useful knowledge about the embossed and printed information found on your typical plastic credit card.

What's The Secret Behind The Luhn Algorithm, Also Known As The "Modulus 10" Or "Mod-10" Formula?

The Luhn Algorithm is the check sum formula used by payment verification systems and mathematicians to verify the sequential integrity of real credit card numbers. It's used to help bring order to seemingly random numbers and used to prevent erroneous credit card numbers from being cleared for use. The Luhn Algorithm is not used for straight credit card number generation from scratch, but rather utilized as a simple computational way to distinguish valid credit card numbers from random collections of numbers put together. The validation formula also works with most debit cards as well.

The Luhn formula was created and filed as a patent (now freely in the public domain) in 1954 by Hans Peter Luhn of IBM to detect numerical errors found in pre-existing and newly generated identification numbers. Since then, it's primary use has been in the area of check sum validation, made popular with its use to verify the validity of important sequences such as credit card numbers. Currently, almost all credit card numbers issued today are generated and verified using the Luhn Algorithm or Modulus, Mod-10 Formula. Needless to say, if you come upon some existing credit card numbers that fail the Luhn algorithm when put to the test, it is safe to assume that they are not valid or genuine numbers.

The one thing to keep in mind is that validity in terms of passing the Luhn test only means that it is mathematically valid for computational compliance purposes. It does not guarantee that the credit card number sequence is indeed a working number that is backed up with a valid credit card account on the card issuer's end. It is not unremarkable for one to artificially generate a mathematically valid credit card number that passes the Luhn validation check, but still ultimately fails as a fake credit card number with no actual substance. The Luhn algorithm only validates the 15-16 digit credit card number and not the other critical components of a genuine working credit card account such as the expiration date and the commonly used Card Verification Value (CVV) and Card Verification Code (CVC) numbers (used to prove physical possession of the debit or credit card).

The Nerdy Process Of Applying The Luhn Algorithm To The Creation and Validation Of Credit Card Number Sequences

For those who hate math or get scared when they encounter a bunch of scary looking mathematical formulas and numerically inspired descriptions, you are not alone. I personally hate math as an academic subject and was rather terrible at it back in high school and college, but if you like visual, thinking puzzles like Sudoku, you'll like working with the Luhn Algorithm. It's pretty clever and remarkably well put together. It's also pretty easy to explain.

  1. First, you'll need to lay out all 15 or 16 numerical digits of the credit or debit card number. The Luhn Algorithm always starts from right to left, beginning with the rightmost digit on the credit card face (the check digit). Starting with the check digit and moving left, double the value of every alternate digit. Non-doubled digits will remain the same. Remember that the check digit is never doubled. For example, if the credit card is a 16 digit Visa card, the check digit would be the rightmost 16th digit. Thus you would double the value of the 15th, 13th, 11th, 9th digits, and so on until all odd digits have been doubled. The even digits would be left the same.
  2. For any digit that becomes a two digit number of 10 or more when doubled, add the two digits together. For example, the digit 5 when doubled will become 10, which turns into a 1 (when 1 and 0 are added together). Likewise, the digit 9 when doubled will become 18, which becomes 9 (as 1 and 8 are added together). Obviously, 0 when doubled will remain 0.
  3. Now, lay out the new sequence of numbers. The new doubled digits will replace the old digits. Non-doubled digits will remain the same. Thus, you should be able to come up with a new sequence of 15 or 16 numerical digits depending on card type.
  4. Add up the new sequence of numbers together to get a sum total. If the combined tally is perfectly divisible by ten (ends in 0, like 60 for example), then the account number is mathematically valid according to the Luhn formula. If not, the credit card number provided is not valid and thus fake or improperly generated.

An Example Of the Luhn Validation Technique In Action - Using Homemade Graphics


For the visual types like myself, let's use the American Express credit card on the right to better demonstrate the doubling and addition mathematics of the Luhn Algorithm. Follow the numbers and you'll realize that it's not as difficult as it may first appear. It's actually very easy once you get the hang of it. You won't look at credit card numbers the same way ever again after you get a good grip of it - I assure you. You'll find yourself testing credit card numbers for fun!

Ignoring the obvious Amex logo on the card, right of the bat it's clear the account number is that of an American Express number - denoted by the numerical prefix - "37". Now let's crunch the numbers through the Luhn Algorithm using the following displayed Amex credit card number: 3759-876543-21001. It doesn't matter if the credit card number sequence has 15 numbers like the American Express or 16 numbers like Visa, MasterCard, or Discover, the Luhn validation check should be able to verify whether this card number is a mathematically authentic credit card number regardless. Follow the Luhn steps from #1 to #4 below, starting with the rightmost check digit.

In this case, the total calculated sum was 57, which is not divisible by 10 (the added up sum does not end with zero). Thus the number fails the Luhn Algorithm validation check. According to the Luhn test, this particular Amex credit card number is completely bogus and fake. The numbers were likely randomly slapped together. To make this particular set of numbers Luhn compliant and error free, all we would have to do is change the all important "check digit" number from 1 to a 4, which would result in a total sum of 60, thereby becoming Luhn compliant.

If you want to test this mathematical theory out in real life, I recommend pulling out your own credit cards and spending a few seconds to run a quick Luhn screening on them just for your own amusement and education. Pretty neat isn't it? If you want another credit card number to test on, try using the credit card number that is displayed on the cartoon "VIZA Card" [sic] that Bart Simpson is holding up in the graphic at the top right of this article - the card is in the name of "Rod Flanders", and the credit card number is: 8525-4941-2525-4158. Tip: Just by looking at the prefix numbers you probably should already be able to tell that the account number's completely random and fake.

Use The Luhn Formula To Validate Existing Accounts But Don't Attempt To Create and Use Fake Credit Card Numbers

Now with this new found knowledge, keep in mind you still won't be able to randomly generate genuine workable credit card numbers. The Luhn theory only allows you to generate mathematically compliant credit card test numbers, not hack workable ones. Besides, without valid expiration dates, and valid CVV2, CVC2, or CID numbers (the special security codes printed on the back or front of credit cards as additional authentication measures), you still wouldn't be able to legitimately use your self generated numbers to run credit transactions anyway.

Cracking and hacking the security codes found on credit cards is currently impossible. To calculate a workable 3 digit CVV2 security code, the algorithm requires a primary account number (PAN), the 4 digit expiration date, a special 3 digit service code, and a pair of DES keys. With such heavy encryption and billions to trillions of numerical possibilities, unless you have God-like mental processing power and a fleet of super computers at your disposal, you won't be able to use brute force guessing attempts to crack the codes.

While it's good to use this type of information to education yourself on the inner workings of credit cards and mathematical validation theory, it's best to stay away from trying to further crack the secret of credit card codes to come up with free workable account numbers. Don't use the Luhn Algorithm for anything else but personal entertainment and amusement.���� Please don't go around trying to generate a list of fake credit card numbers on your own and trying to buy stuff with them. I know some of you out there may be tempted to try, but you'll just get yourself in trouble.

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419 Responses to “Test Credit Card Numbers | Credit Card Validation | Money Blue Book” 

  1. pony says:

    plzz i would like u gimme one complete creditcard to pay 4 my book i only need bout $30 will u help me plzzzz

  2. KASPAROF says:

    It is really pity to see how many people put hope in credit card numbers without trying to understand that nowadays, this kind of fraud is highly punishable.
    - SCAMMERS , remember that uncovered agents are working to help stop that kind of criminal activity.
    To the administrator :
    It is unfortunate that most of this kind of site is becoming an online trading post and forum for credit card scammers and the dubious consumers who keep them in business.
    Nevertheless, keep on doing the right job as your site is useful in many ways.
    Best regards.

  3. zhang qiang says:

    I want to buy a credit card number, please help me, can you use in Canada? How much gold? Silver How much is it? Waiting for your reply, thank you

  4. LOLZ0RS says:

    lol, i went threw every cc # here none of them work DONT WASTE UR TIME SEARCHING 8 HOURS ON GOOGLE FOR ONE JUST GET UR OWN

  5. Gems Rayback says:

    dear friend,

    my real name is ronald g. (rg/gr). my wife was diagnosed with ovarian cyst and we want to order the ebook "ovarian cyst no more by parker" but have no credit card to use. this is only available online for only $39.00. could you please order for us? please we beg.

    thanks and i appreciate your help.

  6. birdy says:

    This is important! My house has recently been destroyed. Theer was a fire in it. I live in a homeless shelter and hope for money. We are allowed on the computer at the shelter for half an hour a day. I have no money at all. I need a credit card number and a cc2. Can someone please give me a credit card number nd cc2. I would like you to e-mail it to me.

  7. WHATTHEFUCK says:

    What the fuck is wrong with you people? No one is gonna give you their credit card details, that's not what it was all about clearly. Get a blooded job you scum of the earth gits.

  8. gems rayback says:

    dear friend, you don't need to publish this comments, i just want to beg again for your help. please order for my wife the ebook we are requesting. you can enter my email address on the order for so the e-copy will be send to me. thanks and may god bless you.

  9. alexlim.pc09 says:

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  10. Samuel Adams says:

    Holy crap! What the hell is the matter with your minds? Someone posts the Luhn algorithm and all of a sudden there are 150 Nigerian onioburus asking for free credit cards. Like, did you even get past the third grade? Sheesh.

  11. Raymond says:

    Samuel Adams,

    You are not completely off base when you write that 150 Nigerians are bombarding me with requests for free credit card numbers. Checking the IP addresses of where the comments re: credit card number inquiries originate, I would have to say that 70% come from African nations. 25% originate from Pakistan, India, and SouthEast Asia, and 5% from North America and Europe.

    I don't know why people get the idea that I have possession of stolen or generated credit card accounts to give away. This blog post was supposed to be an educational blurb about how the mysterious card numbers are created but now it's spawned an exchange market of sorts for illegally obtained credit card numbers. People still continue to email me credit card numbers in the hopes of me buying them or passing the sale information onto other readers. However, I have indicated many, many times now - I DO NOT SELL CREDIT CARD NUMBERS OR EXCHANGE IN STOLEN CREDIT CARD ACCOUNTS. Please stop asking me via email or via comments. Your requests will be ignored and your attempts to include your email or contact information on the site for potential credit card number buyers or sellers will be deleted.

    For all readers, If you want to talk about the Luhn Formula and the mathematical aspects of credit card number generation, feel free to post questions and comments, but otherwise, please don't try to solicit credit card offers or propositions here. Thanks

  12. heather says:

    its sad to think how ignorate people are today! What the hell makes people think someone is gonna just give out credit card numbers over the internet? How retarded!
    If everyone who has asked used even a small portion of their brain, they wouldnt have to beg for someone to give or sell a cc #! Get a life Get a job! Get real! Nothing comes for free and if you think you will never get caught believe me its fun while it lasts but its not worth spending 8 years in prision for credit card fraud like i did! no matter how you look at it, paper or plastic even virtual there is always a trail. Its not worth it!

  13. Raymond says:

    Heather,

    You actually spent 8 years in prison for credit card fraud? I don't know why, but I find that bit of embellishment a bit incredulous and difficult to believe. Anything to back that up?

  14. Faizan says:

    i need valid credit card pls reply me. i need urgent credit card number with cvv pls reply urgent

  15. Single Mom says:

    How do I buy a list of the best free credit card numbers? I'm looking to buy hacked credit card numbers that have been verified and actually can be used in transactions.

    I am a 17 single American mother with 3 baby children...and I live in a trailer home. My baby daddies left us all alone! I also have a 90 year old mother with cancer and she desperately needs medical care and health attention. We need the credit cards to buy things. Please help! I promise it's for a good cause! ^__^

  16. Becky says:

    ok how the hell does this work? Someone fill me in on this.

  17. Free Credit Cards For Sale says:

    I have a few real credit cards for sale. If you want to buy a list of free credit card numbers or free credit cards for trade, let me know. My cousin gets them from somewhere...from his work or something. Haven't tested the credit card numbers out but I believe they are the real deal. $500 each but willing to negotiate for larger quantity. Please don't block my email address - just trying to make a living in this economy and feed my hungry children and wifey. Think of the children!!!

  18. Ampong says:

    i am into gold and diamond business but i need a truthfull partner who is willing to be my partner in this business forever so we can have a good business this is my id : u can email me there and i will reply u soon. i am also in need of one credit card for some purchase of diamond here so please any body who is serious so that we talk about it well thanx and have a positive mind towards the business and it will be a blessing to all of us

  19. faggots -.- says:

    ok, look guys when someone says that there is no possible way for you to get credit cards without applying for one, they mean it. No one in their right mind would give someone a free credit card number just because you "beg" or your wife has a disease or something bullcrap like that.

    Tbh, if you really want a credit card.. Go apply for one.. There isn't a big point in begging.

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