Why are mobile phone and calculator keypads inverted?

Illustration (Photo: Monkey Business Images/shutterstock.com)

Both use the same 10 digits, but are set up differently. The only digit which takes up the same place in both is ‘5’.

The digit ‘1’ on mobile phones is located in the upper left corner, whereas, on computer keyboards, it is in the lower left corner.

It’s easy to forget that phones haven’t always had keypads and that they used to have rotary dials. It seems a bit strange that, once telephones switched from rotary dials to keypads, they didn’t use the setup already present in calculators.

The thing is that, when the company Bell Labs developed the first telephone keypad, they tried out numerous ways of setting up digits before they settled on the best one.

The Bell Labs engineers discovered that people found it the easiest to use the system with 1-2-3 in the top row. And when it comes to phones, their keypads have a function missing from calculators, typing letters, and it makes sense that letters should start from the top.

Why haven’t calculators switched to this setup?

Allegedly, the Bell engineers asked the same question and sought the answer from leading calculator manufacturers. However, neither one of them was able to provide a precise answer. They simply did what they were used to do.

It’s interesting to note that new ATMs use the mobile phone keypad setup.