Why a pendrive/harddrive has less storage space than promised?

Have you ever noticed how manufacturers and our dealers continue to do this again and again without getting sued?

They are not marketing it falsely, but smartly!

While manufacturing a pendrive/harddrive they consider:

1 MB = 1000 KB
1 GB = 1000 MB
1 TB = 1000 GB and so on.

However, our computers work on base 2 and for them:

1 MB = 1024 KB
1GB = 1024 MB
1 TB = 1024 GB

This difference in the method of computation is responsible for this "missing space."

I'll take an example of my 16GB Sandisk pendrive. 
From Sandisk manufacturer's point of view, the 16GB will have 16*1000*1000*1000 = 16,000,000,000 bytes.

From a computer's point of view, 16GB is actually
16*1024*1024*1024 = 17,179,869,184 bytes.

So, my Sandisk pendrive that promises to have 16 GB storage space will actually displays 14.9GB.
 17,179,869,184 - 16,000,000,000 = 1,179,869,184 bytes (1.1 GB) less storage space when connected to a computer.