## Free Tools

Hello everyone. We will have an announcement. Mytoolz.net comes with a new system. In addition, dark mode will be added to the theme. It may take a long time to completely finish and integrate. Tell us your feedback. Have fun.

Fixed: Free CC Checker - Credit Card Checker.

### What is Luhn Algorithm?

The Luhn algorithm is an algorithm developed by Hans Peter Luhn and IBM in 1954. It is also called Luhn Check and Mod Check.

Luhn algorithm is used in 2 ways.

• 1. Preparing a given number according to Luhn algorithm (with check digit value)
• 2. To solve a given number according to Luhn algorithm
• Check digit calculator
Check digit value is a value calculated according to mode 10 over the sum of external check digit values.

The algorithm is as follows:
The rightmost digit is the check digit value.
Starting from the check digit value, we multiply the 1st, 3rd, 5… .. values ​​by 2. (2., 4., 6.… values ​​remain the same.)
If the sum of the values ​​is greater than 9, we add up the numbers and find the sum of the numbers.
All the resulting figures are added together.
The sum of the numbers is multiplied by 9.
The last digit of the obtained digit is the check digit value.