Comments on: What Do Credit Card Numbers Mean? Making Sense of Your Credit Card Number

By: pat garlick

pat garlick — Fri, 12 Aug 2011 15:32:19 +0000

i’ve heard that its not necessary to give out your ccv number? would it be safer not to give out the ccv?

By: Mark

Mark — Mon, 22 Mar 2010 21:06:53 +0000

Is there a way to distinguish a debit issued card versus a credit issued card via the bin when the card is swiped?

By: Aaron

Aaron — Fri, 05 Mar 2010 01:21:43 +0000

Jason, the CVC code on the card is generated by a mathematical function which takes as inputs the card number, expiration date, and a separate unique-to-the-card code which is in the magstripe data but not printed on the card — I wouldn’t be surprised, actually, if that’s the same code value which allows credit card issuers to tell which card was used to make a given purchase. Since this makes the CVC, in turn, also unique to the card, it has to be regenerated every time the card is reissued, even if it’s the only visible change.

By: Aaron

Aaron — Fri, 05 Mar 2010 01:12:49 +0000

R E et al., I’m pretty sure the reason why multiple credit cards proper have identical numbers while multiple check/debit cards don’t is because your credit card number actually is your account number with the issuing bank, while a check card number is nothing like the number of the account it draws on. This implies that there’s a look-up table which maps between card numbers and bank account numbers, and this in turn makes it (relatively) very easy to have more than one check card number on a given deposit account; all you have to do is add another line to the look-up table.

Bryan M, I’m guessing someone who knows that a bare credit card number, all by itself, actually isn’t good for a whole lot, especially when its length would disqualify it from use on just about every payment form on the web — in fact I’m honestly amazed it still works even at a cash register.

By: Bryan M

Bryan M — Thu, 04 Mar 2010 13:25:30 +0000

Who would put their card number as a comment on a public blog…

By: Todd Smith

Todd Smith — Thu, 04 Mar 2010 04:15:19 +0000

4128 131 048 055

That’s been my Visa card # for years and years. They’ve never changed mine to 16 digits.

By: Nickel

Nickel — Wed, 03 Mar 2010 19:12:28 +0000

R E: Now that you mention it, our debit/ATM cards are the same way, but for credit cards we’ve always gotten the same # on both cards.

By: R E

R E — Wed, 03 Mar 2010 18:57:08 +0000

I don’t think that Visa necessarily gives the same card numbers when you have multiple cards per account. My husband and I have a joint account with our bank which gives us Visa check cards, and the last four digits on our cards are different. It could be because they’re check cards and not actual Visa credit cards, but still…

By: Charles

Charles — Wed, 03 Mar 2010 06:47:24 +0000

What about EBT cards? They start with a 5.

By: david

david — Wed, 03 Mar 2010 04:50:46 +0000

As your own referenced page indicates, the check digit indicates the validity of a credit card number, not its legitimacy.

By: Jason

Jason — Wed, 03 Mar 2010 04:02:33 +0000

Visa does issue the same number for multiple cards on the same account but when it is swiped they have unique codes. We called the company about some suspicious charges and they were able to tell us which card it was per transaction. The card companies typically also keep track of online purchases, etc., per billing name with the card so unless you put the other person’s name (which is definitely plausible) they distinguish the cards that way too.

Also, is there any reason why they would change the CCV security code with a renewal? This happened to me and it took a few online purchases to remember, I hate having to reach for my wallet when I know everything else on the card.

By: Online Classifieds

Online Classifieds — Wed, 03 Mar 2010 01:56:53 +0000

Now we know. Thanks for the information. Does it apply for debit cards also?

Charles Wilson

By: Aaron

Aaron — Wed, 03 Mar 2010 00:34:35 +0000

This is a great article! I would, though, briefly pick the nit that ‘Visa’ and ‘MasterCard’ don’t actually issue cards themselves; these associations instead license the use of their brands and infrastructure to companies such as Bank of America and Chase Manhattan, which hold the accounts, issue the cards, and take the heat. The bank numbers are registered with the associations, so they’ll be the same across an entire bank, within whatever set of bank numbers that bank actually owns (big ones like BofA and Chase have lots); the account number is set by the bank itself, and I doubt many of them use a common scheme — some of the digits may mean something, but you’d probably have to get a job at that bank to find out whether and what.

Other than that, again, great article!

By: Greg McFarlane

Greg McFarlane — Sun, 28 Feb 2010 18:48:29 +0000

Nickel:

Amen. I hope I didn’t come across as anti-credit card. I’m only anti-not paying the balance in full every month.

By: Nickel

Nickel — Sun, 28 Feb 2010 13:14:19 +0000

Greg: I’ve heard rumors that the number you’re talking about has something to do with paying interest to the card issuer, but I wouldn’t know… While I use my card regularly, I’ve never paid a dime in interest.

By: Greg McFarlane

Greg McFarlane — Sun, 28 Feb 2010 08:09:23 +0000

What about the number on the piece of paper that came with the card? It was a two-digit number, with a decimal point and a percentage sign. What does that number mean?

I ask because I’m an idiot consumer who buys everything on credit and thinks VISA and MasterCard are screwing me because my balance never seems to go down.

By: Len Penzo

Len Penzo — Sat, 27 Feb 2010 17:37:54 +0000

I’m with Mike. I don’t know why these types of articles fascinate me, but they do.

Thanks, Nickel for the trivia.

I’m still wondering though if the actual account number (for example, the 7th through 15th numbers for a Visa card) can be broken down further?

I’m sick, I know.

Best,

Len
Len Penzo dot Com

By: John @ Hard Work = Blogging

John @ Hard Work = Blogging — Sat, 27 Feb 2010 15:28:29 +0000

Any info on the breakdown of a Discover Card number?

By: Eric

Eric — Sat, 27 Feb 2010 07:21:52 +0000

Don’t ask me why but I already knew all of this. PF geek!

By: Kevin

Kevin — Fri, 26 Feb 2010 22:16:25 +0000

Great article.. this is how some online shopping sites know what credit card your using when you enter the first few numbers.

By: MikeS

MikeS — Fri, 26 Feb 2010 21:27:58 +0000

Thanks. I love useless trivia like this. Allows me to answer some random question later in life and get looks from people on how I knew it.