# 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.

- 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.
- 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.
- 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.
- 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.

October 6, 2009 at 6:29 pmSeriously you guys who do this are so so so so dumb! do you really want to go to jail?

Its called credit card fraud!!!! maybe u have heard of it......its what those dumb mother fucking Nigerian Scammers are doing...don't do this at all!

October 7, 2009 at 3:38 pmI would like a credit card number that i can use online.

With the expiration date and cvv number with credit card number

October 7, 2009 at 5:50 pmFirstly I can not believe that there are so many idiots out there begging for credit card numbers. I am working in this industry, check out our website, where I develop software on banking terminals to process credit card transactions. I generate several thousand credit card numbers at a time, but they are all useless until they are actually issued to a client. Firther more, even if you do have the credit card number you would still require the cvv number on the back of the card. In any event, unless you have the real name, expiry date, cvv number and credit card number, you will not be able to use any credit card number to just do a transaction. with the new EMV compliancy (Euro card - Master card - VISA card) You will soon not be able to do an online transaction using your credit card because the card holder will have to be present, and you would be require to enter a pin. Besides, doing a credit card transaction over the internet, your mac address, IP Address and several other information is being stored, you will be found if making such attempt. Dont kid yourself - There are other ways of making money such as getting of your ass and work for it!

October 7, 2009 at 6:02 pmI have advice though on how to hack a credit card number since this has been requested. This is quite an easy task. Here are the 5 simple steps.

1. Get yourself an axe.

2. Get yourself a credit card.

3. Put the card on a wooden block.

4. Mind the fingers.

5. Hack away.

Happy hacking :)

October 7, 2009 at 10:30 pmi need 1 for a website and i dont want girlfriend finding out

October 17, 2009 at 10:13 ami hope u guys get in trouble thats not right hacking credit card numbers and don't believe anyone and pay him money he will just rob ok just telling u guys would just rather work and buy what u want

October 17, 2009 at 10:15 amoh and this website the FBI knows about it and it knows each one of ur house by ur ip address so u will get arrested for any wrong thing u say warning ya U WILL GET IN ALOT OF TROUBLE JUST TELLING YA

October 18, 2009 at 6:04 pmMaybe I was the only one who read the part about NOT attempting to utilize this info for illegal means:-( Wow you guys are amazing.

October 18, 2009 at 9:37 pmi need to pay for things i bought,but is through,western union and bank transfer.if u can help me 50 50 or i pay for it

October 20, 2009 at 4:50 pmhey if youcan give me your credit card number i will love that, it will only cost you $5 for the thingi need...plzgiveme all the information of your credit card thankyou

October 23, 2009 at 7:11 ami need a valid cc with expiring date am an ophan

October 25, 2009 at 2:39 pmplease i am an ophan i need a valid card number for my money

October 25, 2009 at 9:49 pmhey plz send me a detail of valid credit card

1. Card number

2. cvv number

3. expire date...

in other require detail

plz send it to me ...soon

with best regards

Lucky Singh

October 26, 2009 at 3:21 pmMastercard

5442518721267504

5136636265926870

5122164683304675

527444081356 3729

5347312005410089

5256607510083803

5417238292393115

5476896970786120

53 86815144456021

5311980788659817

VISA 16 digit

4916971496931640

4716920895887079

4556504464880237

4556850370688531

4 929076020768578

4485122700346768

4532563640407694

4929852652009865

4944703 481780203

4024007155538068

VISA 13 digit

4024007165000

4024007198977

4024007185081

4929587098092

4539772651363

American Express

370018517805614

345815714781056

378398390252031

345036527099467

376 328268007136

Discover

6011337697052231

6011127803546360

6011273086329197

Di ners Club

36274402316854

30264894758958

38007557889467

enRoute

201479533438183

21 4947995886961

201443923497183

JCB 15 digit

210052791888925

180021707668107

180032214040318

JCB 16 digit

3112720079297364

3096551384606019

3088042082812992

Voyager

8699189543 50867

869971087198240

869923304693818

October 27, 2009 at 5:50 amAnd exactly what are you going to do with these numbers without the cvv and expiry info?

October 27, 2009 at 3:13 pmThe list of credit card numbers above are all pretty useless without the appropriate accompanying cardholder names, expiration numbers, and 3 digit CVV codes.

As the primary moderator of this blog, I do immediately delete, censor, and filter out the confidential credit card numbers that actually prove to be legit - to prevent others from committing fraudulent acts. So those of you thinking of posting actual, real, and working credit card numbers that you've stolen or hacked, please don't. But feel free to post test credit card numbers for Luhn Algorithm validation purposes pursuant to the spirit of this blog post. Just don't publish real working credit card numbers with all of the pertinent personal data for the number to be actually used by unauthorized individuals. Thanks

October 29, 2009 at 12:25 pmplz i need credit card number to masterbate to. CREDITcards make me horney!!!

November 1, 2009 at 11:45 ammy name is seth i need a free credit card for the payment of my fees

November 4, 2009 at 1:23 pmRaymond im asking for a prepaid credit card with no money on it. NO MONEY on it

can someone give the me the info to a pre paid credit card that has no cash on it. i want to get like free usenet trials but they ask for a credit card but they dont charge it. they only ask for it if you decide to start a pay account after the trial. if someone could help me out then that would be great. by the way im looking for a prepaid credit card.

November 7, 2009 at 9:22 amcan someone plz tell me a valid cc # with the security code, name of cardholder and expiration date!

Thanx that would be so helpful and the only reason i need these are for charity purposes... please :[