What is the correct method to write measurements in English?

Question

Should it be: **1KG** or **1 KG**? **1M** or **1 M**? **1PM** or **1 PM**? **1GB** or **1 GB**? **1Kmph** or **1 Kmph**? **1Kbps** or **1 Kbps**? or anything else?

Answer 1

I have seen both uses. Here's an example that uses the more formal presentation: At the Earth's surface, a mass of 1 kg weighs approximately 2.20 pounds (lb). Conversely, an object that weighs 1 lb at the Earth's surface has a mass of approximately 0.454 kg