# Why is the number keypad different on the phone and the calculator?

### And if so, have you ever wondered why?

The calculator design came first, so let’s look at how that came about. It was based on the existing shop cash register where the zero was placed intentionally at the bottom because it was the most common number used when keying in currency amounts. And because 1 and 2 were the most common monetary amounts, these numbers were also placed at the bottom to be nearer the zero for ease of keying. So that’s why 1, 2, 3 are at the bottom and 7, 8, 9 are at the top.

So why was this accepted layout changed for the touch-tone phone and everything involving number keypads ever since?

Here are some theories …

### Theory 1:

The calculator keyboard was widely accepted by the time the touch-tone phone came about in the 1950s. People were used to typing the numbers really fast for data entry. But this familiarity and speed wouldn’t work for the touch-tone phone as the tone recognition technology wasn’t advanced enough to recognise the numbers keyed at such speed. So the telephone designers reversed the number layout to slow fingers down.

### Theory 2:

A study by Bell Labs in 1960 revealed that laying the numbers 1, 2, 3 at the top was the easiest number configuration for people to use.

### Theory 3:

People had been used to the rotary dialling phone which started with 1 on the top right and zero at the bottom. They wanted to use the same configuration for the touch-tone phone but it didn’t make sense to have the number 1 at the top right since reading went from left to right not right to left. So they started with 1 on the left and zero naturally fell at the bottom.

Whatever the reason for the change, the phone layout is today the accepted layout for all new products requiring a number keyboard, including ATMs, but our trusty calculators remain as they have always been.

Recent Posts