The primary way for people in most countries around the world to measure distance or size is with the metric system. This consists of a series of units which are arranged in an exponential scale. A centimeter is a hundred millimeters, a meter is a hundred centimeters, a kilometer is a thousand meters and so on. It’s a very easy system to use so it should come as no surprise that the vast majority of the world thinks that it is the only standard worth focusing on or regularizing at the end of the day.
That said, things can be quite different if you visit the sole global superpower in the world. People living in America usually rely on imperial units mostly because of the fact that they have not yet moved on to the superior metric units that so many are preferring. This is problematic due to the reason that you often need to rely on American standards for lots of things such as how big your Metal Kards should be if you want them to conform to global business requirements.
This size is usually displayed in inches which makes it hard for metric users to decipher. If you want the size in millimeters, you should know that it is around eighty nine millimeters in width and fifty one millimeters in height. This is not as precise as the inch based measurements so you might want to brush up on your imperial measurements so that you can figure out what the most accurate kind of optimal size would be for your business cards. More people should learn both systems so that they can make the most of them.