Pen drive of 2GB PC 1.86 GB Why do's?

I have a 2 GB pendrive PC attached to your computer, but on the PC to the Czech in the space of 1.8 GB is going to show, not only with me but that only will happen to you.

This does not mean the same as 2 gb and 1.8 GB space to any company in fact equal to 1 * 1000 is 1000 MB.
Means 1000 * 1000 * 1000 = 1,000,000,000 bytes = 1000000 1000000 kb and the computer calculates.
1000000000/1024 = 976,562.5 kb ;
976562.5/1024 = 953.67 MB
953.67/1024 = 0.93 GB
In this manner is 2 GB pendrive 1.86 GB show .

The standard hard disk by companies

1 KB = 1000 bytes
1 MB = 1000 KB
1 GB = 1000 MB
1 TB = 1000 GB

Computer hard disk standard

1 KB = 1024 bytes
1 MB = 1024 KB
1 GB = 1024 MB

1 TB = 1024 GB