**Test Credit Card Numbers** – Card Verification Value, also known as CVV is a secret code number or security code located on the back of credit card or debit. This number consists of 3 – 4 unique numbers. the secret code on the credit card serves as a manual authorization number that aims to make transactions.

Credit cards are generally used for online transactions. Or shopping at malls and mini markets. Credit card numbers are much needed for shopping. There are several things you should do when you want to shop online such as Name, zip code, expiration card and CVV. All that is very important to avoid a scam.

If all is valid, you will get payment approval and get bill sent via SMS or Email…..

## How to Test Credit Card Numbers Valid Or Invalid?

Did you know that credit card numbers use an algorithm called Luhn. Luhn formula, also known as the “modulus 10” or “mod 10” algorithm, is a simple checksum formula used to validate a variety of identification numbers, such as credit card numbers….

First Count:

Digits 1: 5; 5 × 2 = 10 {More than 9}, so 10 – 9 = 1

Digits 3: 7; 7 × 2 = 14 {More than 9}, so 14 – 9 = 5

Digits 5: 5; 5 × 2 = 10 {More than 9}, so 10 – 9 = 1

Digit 7: 3; 3 × 2 = 6 {Leave it alone, because LESS THAN 9}

Digit 9: 1; 1 × 2 = 2 {Leave it alone, because LESS THAN 9}

Digits 11: 4; 4 × 2 = 8 {leave it alone, because LESS THAN 9}

Digits 13: 8; 8 × 2 = 16 {More than 9}, so 16 – 9 = 7}

Digits 15: 5; 5 × 2 = 10 {More than 9}, so 10 – 9 = 1

Then add up:

1 + 5 + 1 + 6 + 2 + 8 + 7 + 1 = 31

Count of Two:

Take the even number of digits from the number 5376-5438-1045-8356 then sum it up

Digits 2: 3

Digits 4: 6

Digits 6: 4

Digits 8: 8

Digits 10: 0

Digits 12: 5

Digits 14: 3

Digits 16: 6

———- +

The result = 35

Third Count:

Take and sum up the results of first and second counts:

31 + 35 = 66

This is best ways for **How to Test Credit Card Numbers Valid Or Invalid** and note: The result of the third count should be divisible by “10” if it still leaves the decimal number and not exhausted it can be said the credit card is not valid and can be said credit card is NOT VALID to be used. (The result of the third count above is 66 if divided by 10 then the result 6.6 still leaves the decimal number, it can be concluded credit card numbers listed above NOT VALID or invalid or can not be used)