Why isn't the entire space of a Pen Drive/external Hard Drive/Memory Card available for Storage?

Have you ever thought what is the reason behind, you tend to get less amount of storage in comparison to the storage device that you have purchased, for example when you buy 16 GB Pen Drive, it shows 14.9 GB of Storage on your Computer or Laptop. As in the Image below a 4 GB pen drive is inserted and it is showing 3.72 GB is free.

Well, this is not a mistake that is made by the manufacturer of the device or it is not mistake made by your Computer that it is showing less amount of storage in comparison to the actual one.

In this article of mine, I am going to tell the actual reason behind this happening and believe me after reading this, you surely will get to know why you see less storage space when you plug in your external storage device on your Computer or Laptop.

Let us get Started:

This is just a simple calculation:

When manufacturers like SanDisk or any other manufacturer make pen drives, hard disks(talking about the external one) etc. they design the capacity in multiples of 1000 or 10^3.

However computer reports capacity in multiples of 1024. From our school days, we are learning that 1024 Bytes is equal to 1 KB and 1024 KB is equal to 1 MB and so on. But when a manufacturer makes a pen drive or some hard disk, they don't take this number, in order to make the calculation simple and precise they take the amount of capacity in multiples of 1000 like they take 1000 Bytes are equal to 1 KB rather than 1o24 Bytes and so on.

Hence when you insert a x GB hard disk or pen drive in your computer, you can expect the capacity of a drive to be below x GB when reported via the computer.

Let’s take the example of  a  16 GB pen drive, then according to the manufacturer

16 GB = 16,000 Megabytes = 16,000,000 (or 16 million) Kilobytes = 16,000,000,000 (or 16 billion) bytes.

But when you insert it into your computer, you say it reports 14.8 GB. Here’s how:

16 GB becomes 16,000,000,000 / (1024^3) = 14.9 GB. [ Dividing by 1024 once for each conversion i.e from Gigabyte to Megabyte, Megabyte to Kilobyte and finally from Kilobyte to Byte].

Manufacturers don’t commit this error/fraud with the intention of robbing you. It’s just that in commercial terms it’s easier to calculate things as multiples of 10 (10^3 or 1,000 in this case), than as a multiple of 1024, which is how the computer understands the capacity of the drive.

Most of the people come with a myth that the actual storage is the size of the unformatted disk and when the disk or the drive gets formatted the drive reserves some space for itself and the storage goes down. However, it is not like that, It is for simple calculation manufacturer go this way. 

Whereas the truth is that of course, the drive will have to be formatted according to a file system that is supported by both the drive and the computer [which is FAT32 for drives up to 32 GB capacity and exFAT for drives between 64 GB to 256 GB].

Have a look at the packaging of your pen drive/memory card.

At the bottom, you will find a fine print marked by an * declaring “1 Gigabyte equals a Billion bytes”. Manufacturers are smart to include this line so that they don’t face lawsuits from customers after the purchase of their storage devices.

That's it in this article of mine, I hope now you guys have a clear idea behind this methodology of storage devices and now if someone ever gets a little bit confused cause of this difference in storage available, you will be able to help them out.

Source of Information: Quora.com