How to Tell if a Credit Card Is Fake in Under 60 Seconds


eHow Money Blog

A little-known fact is that every single credit card number conforms to something called the Luhn algorithm.

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We can’t believe your credit card never told you about Luhn either.

Your credit card has a secret-aside from the 40 bucks you racked up on Ventis this week.

A little-known fact about these ubiquitous pieces of plastic is that every single credit card number conforms to something called the Luhn algorithm.

What’s that? Basically, it’s a formula you can use to check any credit card number. Also, we’re pretty sure there’s a neat party trick in there somewhere.

Here’s how it goes. Using your own card, or the card below, try the following:

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  • Starting with the second-to-last digit of the credit card number (in the example above, a 7), double every other digit on the card number. For the card above, your numbers would be as follows: 8 5 14 8 8 5 12 2 10 6 8 3 18 1 14 3.
  • Take any double-digit numbers you have and add each digit to make it a single digit (that means 14, 12, 10, 18 and 14 in our example). So your numbers are now: 8 5 5 8 8 5 3 2 1 6 8 3 9 1 5 3
  • Add up all of these single digits (8 plus 5 plus 5 plus 8, etc.).

Is the sum for your card divisible by 10? All credit, debit and bank card numbers are. That’s why it’s also called a “Mod 10 check.” If it isn’t divisible by 10, you either miscalculated (understandable), or you somehow got your hands on a fake, like this one. (Sorry, did the “Your Credit Card” part ruin the surprise?)

Now go tell your friends you’re psychic/a genius and wow them with this little trick.

How Do We Know All This? Cuz we’re brilliant. Also:
The ISO knows what’s up-they call the shots.
Hey, another fake credit card number. What are the chances?

-Ariel Dreyer, Serious Coin Contributor

Photo credit: Robert Llewellyn/Workbook Stock/Getty Images and Aaron Foster/Photographer’s Choice/Getty Images

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