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

It's standard to use a space between number and unit; thus "1 kg", "1 GB", etc.