Card validation is a process to check if a credit card is valid for online purchases or not. There are pre and post validation processes.
There are 4 sections of a credit card. Luhn Algorithm Check, Major Industry Identifier, Issuer identification number and Personal Account Number
Credit card numbers are generated according to certain rules. It gives merchants a way to verify the validity of a card number before accepting the customer's payment.
The calculation to compare a credit card number with your checksum is known as the Luhn algorithm.
To understand the composition of a credit card number, we can break it down into four parts:
While the general layouts of all the credit card networks are closely similar, there are some minor distinguishing differences.
It is worth noting that other than the card number format, the rest of the details i.e., the expiry date, CVV and accountholder name are all written the same way in all layouts.
Coming back to the point, there are four major credit card networks in the world: Visa, Mastercard, American Express and Discover.
Visa cards have two distinct features in their card numbers:
These are some examples of standard Visa card numbers:
4956 6185 5002 8752
4081 9806 2935 3449
Mastercard cards can be identified by these two characteristics:
Some examples of Mastercard card numbers:
5453 6809 6059 3325
5492 2479 2143 8645
3. Amex (American Express)
The number layout in Amex cards has these two qualities:
Some examples of Amex cards are:
3718 5810 1319 293
3499 2979 0395 594
Discover card numbers can be identified by the following features:
Some examples of Discover cards are:
6011 2653 9018 9036
6011 8328 2589 7994
How to Manually Check the Validity of a Credit Card Number Using the Luhn Algorithm
It may sound complicated but running the Luhn algorithm on any set of numbers isn’t actually that hard.
You could do it in a couple of minutes using a pen and paper…if you wanted to.
To understand the working of the algorithm, let’s take a random card number as an example i.e.:
6011 8328 2589 7994
These are the steps that you need to follow to manually check the validity of any card number against the Luhn algorithm.
Starting from the right side of the string, take every alternating digit and multiply it by 2.
In this example, they would be:
6011 8328 2589 7994
If any number becomes more than 9 after being multiplied, add both of its digits together. For example, 6 x 2 = 12. Since 12 is more than 9, we add up both the digits: 1 + 2 = 3.
The new number, after applying this step, becomes:
3021 7348 4579 5994
Next up, add all the digits together.
3 + 0 + 2 + 1 + 7 + 3 + 4 + 8 + 4 + 5 + 7 + 9 + 5 + 9 + 9 +4
If the sum of all these digits is a multiple of 10 i.e., it ends with 0, it will satisfy the Luhn algorithm.
3 + 0 + 2 + 1 + 7 + 3 + 4 + 8 + 4 + 5 + 7 + 9 + 5 + 9 + 9 +4 = 80
In this case, the answer is 80, which means that this number satisfies the Luhn algorithm.
In the example above, the credit card number was fully formed i.e., it had a checksum or a ‘check digit’ at the end.
However, if a card number does not have the checksum at the end, we can apply a formula on the other digits and compute it manually.
Take this number, for example:
This is an incomplete number since it does not have a check digit at the end. The combination of numerals other than the checksum is known as the payload.
The steps for the checksum computation are initially the same as the Luhn algorithm procedure.
Every alternating digit, starting from the right, has to be multiplied by 2. If the sum goes in excess of 9, the two digits will be added.
The resultant numbers will be:
After the number has been generated according to the step above, add them all together.
In the case of this example, the sum will be 67.
This is the formula that is applied to the sum of the values in order to generate the checksum:
((10 – x mod 10) mod 10) = x
In our example, the formula will become:
((10 – 67 mod 10) mod 10) = 3
‘3’ will be the checksum.
It is important to keep in mind that whenever fraudulent cards are used, the merchant loses. The customer of a stolen credit card is not hooked, and the credit card companies are generally not affected.
However, the merchant generally stays away from the product or service provided, as well as the resources necessary to discover the fraud and fight against the credit card company. And if too many fraudulent transactions occur, you may incur higher processing fees, expensive chargebacks, or even losing your merchant account and your ability to do business.
But you can mitigate these risks with the help of a little automation, and we can help you! Simply use our online card validator tool and our tool help you to combat fraud and maximize the sales of your credit cards.
Absolutely not! The credit card number entered in our validator was made using the validation rules. However, we do not store these credit cars for security reasons.