Why do the calculator and the phone not share the same number placement/ pattern?


The numbers on the phone pad start with 1 in the upper left corner, going down to 9 in the bottom right corner.

The numbers on a calculator start with 1 in the bottom left corn, going up to 9 in the top right corner.

For example, the top left number on a phone pad is 1. The top left number on a calculator is 7.

This difference makes it challenging to switch between the two. Why were they designed this way?

In: Engineering

Both layouts were a result of a need to increase efficiency/productivity in their respective industries.

The calculator layout was made for bookkeepers and found it increased their speed and efficiency.

The phone layout was made to decrease the amount of wrong numbers that were dialed by people using phones, as that layout appeared to be more easily understood by most people and re-directing calls made to the wrong number caused increased workload on phone operators.

Maybe I take for granted that I grew up with regular phones and texting with T9, but I never considered it would be challenging to switch between the two.

I long ago read (so don’t recall the source) that when phones first moved from rotary to the standard layout, people with a lot of experience on calculators were dialing too fast and digits were being lost/skipped. They switched the layout to slow people down just long enough for the technology to catch up

I’m pretty sure that it’s because the alphabet code layout on the rotary phones wouldn’t have a logical layout if it used the adding machine layout.

I think the basic idea is the to consider the position of the hand while using the devices.

Calculators are usually used while sitting at a desk where more often than not, your hand lies at the bottom of the calculator. Your hand is more familiar going forward than backward, so numbers starting from bottom are intuitive.

Mobile phones on the other hand are hand held, and you use your thumb to press keys. From a natural hand position, the thumb is quite flexible and can move in random directions easily (thanks to joysticks and smartphones human thumbs are more precise than ever… XD). So the number pad is placed upright just so that it looks less confusing.