The reason behind ATM’s 4 digit pin code

You walk into your friendly neighborhood ATM kiosk and swipe your card. You then punch in a 4-digit PIN code to authenticate yourself and proceed to withdraw money. You may have been doing this mechanically since the day ATM was introduced but have you given a thought why ATM PINs have a 4 digit code?  No! Then read on..

Automated Teller Machines (ATM) were first introduced in 1967 and now have emerged as a best option to disburse cash. Instead of visiting your bank and waiting in a long queue to withdraw money, you just have to swipe your ATM card, punch in your secret 4 digit PIN and take away the money you require.

But if someone has found or steal your card, the only barrier protecting your money is your 4-digit ATM PIN. Ever wondered why most PINs have only 4 digits? Given that an ATM dishes out money, wouldn’t the manufacturers of ATMS have been wiser to introduce a longish PIN say six digit or eight digit one. Isn’t that why our email passwords are also expected to be 6 letters or more?

You see there is a bit of story behind it. ATM was invented by a well known Scottish inventor John Adrian Shepherd-Barron, the man who pioneered the development of the ATM machine. Barron was born in Shillong and was son to a Wimbledon ladies doubles champion, Dorothy Barron. When testing out his invention, Barron had also proposed a 6-digit PIN.

However, the first person to use his invention was his wife, Caroline. We all know that behind every successful man is a woman, and Caroline apparently rejected the idea of using a six code PIN for her husband’s invention because she could only remember the numbers up to four.



Reportedly, 6 numbers stringed together were too much information for her to recall.

Although, there are many banks nowadays that offer 6 digit PINs for security purposes, shouldn’t those of us using 4 digit PINs be thanking Caroline? It gets tough to recall those 4 digits at times, imagine what 6 or more would do to us?