Well, we don’t have enough time to know everything. However, the reason behind this is little funny. So, it will be worth knowing why ATM PINs always have 4 Digit Code. ATM (Automated Teller Machines) was first introduced in the year 1967 and it had been widespread in no-time. Instead of visiting the bank and waiting in a long queue to withdraw money, you just need to swipe your ATM card, insert your secret 4 Digit PIN code and obtain the money you require. Let’s come to the point and know why ATM only have 4 Digit code instead of 6 or 8 digits. ATM was invented by a well-known Britisher John Adrian Shepherd-Barron. He was born in Shillong and was born to Dorothy Barron (Wimbledon Ladies Double Champion). While testing his invention John Adrian Shepherd-Barron proposed for a 6-digit PIN. The first person to use his latest invention was his wife, Caroline. Caroline apparently rejected the idea of using a six-digit PIN for her husband’s invention and the reason behind it was surprising. Caroline rejected the idea of putting the 6-digit code for her husband’s invention just because she could only remember the largest string of 4-digits. So, 6-digit was too long for her to recall. So, this was the reason why ATM PIN has only 4 digits. Nowadays there are many banks that are offering a 6-digit PIN code for accessing the Debit cards. However, sometimes we even forget our 4-digit code. Just imagine what can happen if the PIN was of 8 digits like we use it on our social media accounts. So, let’s thank that woman.