You Can Spot a Fake Credit Card Yourself!
Signing up for credit cards through partner links earns us a commission. Terms apply to the offers listed on this page. Here’s our full Advertising Policy.
I’ve written about how the numbers on a credit card actually contain a lot more information than most folks think. For example, you can find out the card category (Visa, MasterCard, etc.), issuing bank, country, and even type of card (World MasterCard, Visa Signature, business, etc.) just from the 1st 6 digits!
But did you know you can use the last digit of almost any credit card number to figure out if the card is a fake? All it takes is a little bit of math. I’ll show you how!
How Do You Do It?
The last digit of any credit card number is called the check digit or checksum. Its only purpose is to validate the credit card number.
Credit card issuers use a formula called the Luhn Algorithm to create the check digit. And you can use the same formula to figure out if a credit card number is phony!
Let’s use the generic credit card number from the Barclaycard Arrival Plus World Elite Mastercard website as an example:
Here’s how to do it (math alert!). 😉
1. Drop the Last Digit (the Check Digit)
First, drop the last digit from the card number. So 5412 7500 1234 5678 becomes:
5412 7500 1234 567
2. Reverse the Digits
In this case, reversing the digits gives us:
765 4321 0057 2145
3. Multiply Odd Digits by 2
Starting with the 1st digit, multiply every other digit by 2. So now we have:
(14) 6 (10) 4 (6) 2 (2) 0 (0) 5 (14) 2 (2) 4 (10)
4. Subtract 9 From Any Numbers Over 9
Then, subtract 9 from any double digit number that results. For example, the 1st number is now 14, and 14 – 9 = 5 So now you get:
(5) 6 (1) 4 (6) 2 (2) 0 (0) 5 (5) 2 (2) 4 (1)
5. Add All the Numbers Together
Add all the numbers. So in this case:
5 + 6 + 1 + 4 + 6 + 2 + 2 + 0 + 0 + 5 + 5 + 2 + 2 + 4 + 1 = 45
6. Add the Check Digit
Remember the check digit we dropped at the beginning? In this case, it was 8. Add it back to the sum:
45 + 8 = 53
7. Is the Number Divisible by 10?
If the final number is divisible by 10, then it could be a valid credit card number.
If it’s NOT divisible by 10, it’s definitely NOT a real credit card number. In this case, 53 is NOT divisible by 10, so it’s a fake credit card number!
Here’s another way of looking at it. The check digit is the number you would have to add to the sum (from running the card number through the algorithm) to make a number divisible by 10.
So in our example, the sum was 45. The check digit would have to be 5 for this to be a valid credit card number, because 45 + 5 = 50, and 50 is divisible by 10!
If You’re Not in the Mood for Math
Instead of doing the math yourself, you can also enter a credit card number into this free Online Credit Card Validator. It’ll run the calculations for you and tell you if a card number is (potentially) valid or definitely fake.
If you enter the Barclaycard Arrival Plus example, this tool tells you right away it’s invalid.
But if you change the last digit to a 5, it says it is valid.Note: I would NOT enter your real credit card number, because it’s not an encrypted site. Even though a thief would probably still need your name, expiration date, and verification code, it’s better to be safe!
A credit card number is not just a random sequence of digits. And the last number, the check digit, is used to validate the credit card number.
By doing a little math (or using a free online tool), you can figure out if a credit card is fake.
Chase Sapphire Preferred® CardAPPLY NOW
Chase Sapphire Preferred® Card
Earn 60,000 bonus points after you spend $4,000 on purchases in the first 3 months from account opening. That’s $750 toward travel when you redeem through Chase Ultimate Rewards®
2X points on travel and dining at restaurants worldwide, eligible delivery services, takeout and dining out & 1 point per dollar spent on all other purchases.
Get 25% more value when you redeem for travel through Chase Ultimate Rewards®. For example, 60,000 points are worth $750 toward travel.
Get unlimited deliveries with a $0 delivery fee and reduced service fees on orders over $12 for a minimum of one year on qualifying food purchases with DashPass, DoorDash’s subscription service. Activate by 12/31/21.
Earn 2x total points on up to $1,000 in grocery store purchases per month from November 1, 2020 to April 30, 2021. Includes eligible pick-up and delivery services.
Either $5 or 5% of the amount of each transfer, whichever is greater.
Editorial Note: We're the Million Mile Secrets team. And we're proud of our content, opinions and analysis, and of our reader's comments. These haven’t been reviewed, approved or endorsed by any of the airlines, hotels, or credit card issuers which we often write about. And that’s just how we like it! :)