Yeah, that "metric" system is real standard:
but do you mean ISO metric, DIN metric, or JIS metric?
Where we've adopted the metric system in this country, it's been the ISO system, in which the fasteners, for example are generally incompatible with DIN (German) and JIS (Japanese) metric fasteners.
As an engineer and a scientist, I use the Imperial system exclusively, and whenever I need to convert, why, there's always a calculator handy.
Some years ago I had a lot of fun with a group of Europeans who were giving me a bad time about when we would convert. I told them that we were waiting on them to decide which metric system to use. They got into a big argument among themselves with the Dutch and Germans re-fighting WWII and the others taking sides. I didn't have to defend our system any more that night.