Have you ever wondered what those digits at the end of your bank account number mean? Those are check digits, and they play a crucial role in ensuring that your transactions go smoothly. In this article, we’ll explain what check digits are, how they work, and why they matter. By the end, you’ll have a better understanding of what your bank account number means and how it’s kept secure.
What is a check digit?
A check digit is a single digit that’s added to the end of a bank account number to help prevent errors. It’s calculated using a mathematical formula that takes into account the other digits in the account number. The idea is that if any of the preceding digits are changed or mistyped, the check digit will no longer be valid, alerting the bank to the mistake.
How are check digits calculated?
The exact formula used to calculate check digits varies depending on the algorithm used by the bank. However, the most common method is the Luhn algorithm, also known as the mod-10 algorithm. This algorithm works by taking each digit in the account number, starting from the rightmost digit, and doubling every other digit. If the doubled digit is greater than 9, the two digits are added together to create a single digit. The algorithm then adds up all of the resulting digits, including the original digits that weren’t doubled. The check digit is the number that needs to be added to this sum to make it divisible by 10.
For example, let’s say your account number is 12345678. To calculate the check digit, we would:
- Start from the rightmost digit, which is 8.
- Double the digit to get 16.
- Add together the two digits in 16 to get 7.
- Move to the next digit, which is 7.
- Leave this digit as-is, since it’s not being doubled.
- Move to the next digit, which is 6.
- Double the digit to get 12.
- Add together the two digits in 12 to get 3.
- Repeat this process for each digit in the account number.
- Add up all of the resulting digits to get 37.
- Find the number that needs to be added to 37 to make it divisible by 10, which is 3.
Therefore, the check digit for the account number 12345678 is 3.
Why are check digits important?
Check digits are important because they help prevent errors and fraud. If a digit in the account number is mistyped or changed, the check digit will no longer be valid, and the bank will be alerted to the mistake. This can help prevent transactions from being processed incorrectly or fraudulent activity from taking place. Additionally, check digits can also help banks catch errors in their own systems, ensuring that all transactions are processed accurately.
How can I check my bank account number?
If you’re not sure what your bank account number is or what the check digit is, you can usually find this information on your bank statement or by logging into your online banking portal. Alternatively, you can call your bank’s customer service line and ask for assistance.
What should I do if there’s an error in my bank account number?
If you notice an error in your bank account number, such as a mistyped digit or missing check digit, you should contact your bank immediately. They may be able to correct the error and ensure that your transactions are processed correctly. Additionally, you should always double-check your account number before initiating any transactions or providing it to others.
Conclusion
Check digits are a simple but effective way to ensure the accuracy and security of bank account numbers. By adding a single digit to the end of the number, banks can help prevent errors and fraud, keeping customers’ money safe. If you’re not sure what your bank account number is or how the check digit works, don’t hesitate to contact your bank for assistance.