Which systems of measurement are used across the world?

In Asia, it is Metric system (Kg/m/h)

In Europe, it is mainly British Units a.k.a Imperial Units (FPS) and in America it is the American Engineering Units.

Be very mindful of how the units are converted from one system to another, one wrong conversion unit can have a very bad repercussion to it. It is also a good industry practice to stick to one set of units across a set of calculations.

Hope this helps.

Most of the countries are using SI standards and some of countries use FPS system.