How to calculate “USB Flash Drive / Hard Disk / SSD” Capacity

Why do USB Flash Drive or any computer storage devices shows lesser capacity as advertise in the product? For instance, an 16GB USB Flash Drive displays 14.9 GB available space that it can save data. It’s all about the marketing plan devised by the marketing people!

An Appetizing Sushi USB Flash Drive
Sushi USB Flash Drive Design

You see, marketing people need to sell product, and the better they can make the product look, the better it should sell. So what happened a while back is that they decided that 1MB shouldn’t equal 1048576 bytes. Instead, it should equal 1000000 bytes. 1GB should equal 1000000000 bytes instead of 1073741824 bytes.

This way, when you take 16000000000 bytes you can call it 16GB in the packaging, but computers use base 2 math, which converts 16 billion bytes into 14.90 GB of real space. It is mostly a situation of semantics.

Here’s some math from Marketing:

1KB = 1000 bytes (10^3)
1MB = 1000000 bytes (10^6)
1GB = 1000000000 bytes (10^9)

Whereas a computer believes:

1KB = 1024 bytes (2^10)
1MB = 1048576 bytes (2^20)
1GB = 1073741824 bytes (2^30)

So if you take your 16GB on the packaging, convert it to 16 billion, then divide by 2^30, you get 14.90, which is what the system will report as the size. This is common with Flash drives, Hard disk drives, etc.

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One thought on “How to calculate “USB Flash Drive / Hard Disk / SSD” Capacity

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