The standard system of units was created to simplify calculations and unite the world. Still, old traditions prevail in some countries and they stick to inches, yards and miles. Sometimes even common measurements are done with their utilization. For instance, the screen of any modern gadget is usually given in inches. Let’s discover how to transform Inches to mm and what is the ratio between these units.
The story of an inch
There are several opinions on the origin of the word inch. Thus, there is the Dutch word duim, which means a thumb, and German Daumen has the same meaning and similar pronunciation. Anyway, at the beginning of the story, this term referred to the width of the thumb of an adult male.
Stories concerned with the origin of the inch are more romantic. For instance, the British prefer the one that tells that this option was derived from the yard. The latter corresponded to the distance between the thumb and the tip of the nose of the English king Henry I. Another legend claims that the distance was measured according to the lengths of the king’s famous sword. In any case, an inch was considered one thirty-sixth of a yard.
Another less romantic story tells that once King Edward I issued an edict stating that one inch must be equal to the length of three barley grains put together in a row. These grains must be extracted only from the middle part of the ear. Interestingly enough, even in modern Britain, one may hear about a length equal to a third of an inch as a barleycorn.
British still give preference to inches over other options are never write them down using decimals. These numbers should be expressed as ordinary fractions with a denominator multiple of two.
As for the millimeters, they belong to the standard options. It is well-known worldwide as one-tenth of a centimeter.
How to convert inches to mm?
Before we discover how to transform inch to mm, we have to find out their ratio. The latter has been changing over time, namely, 1 inch to mm was equal to:
- approximately 1819 in 25.400438;
- 1922 in 25.39956;
- 1947 in 25.399931.
Only in 1958, it was decided to utilize 1 cm or 2.54 mm as an option equal to 25.4 inch. Since then, the transformation of in to mm has become more organized and unified.
Therefore, if you need to calculate 1/4 inch to mm, you just have to use this multiplier and the result will be as follows: 1/4 x 25.4 = 6.35 mm.
This calculation is useful for those who are purchasing mobile phones, tablets or laptops, as their dimensions are still always given in inches. For instance, phones have screen sizes ranging from 3 to 7 inches. However, it should be measured together with the density in pixels. The higher this indicator, the better the quality of the images.