Tech Tip – We hear and read terms like megabyte and terabyte used to describe the size of digital storage all the time. But do you really know what they mean?
The most common and smallest term of measurement is the kilobyte. Kilo means 1000. So you would think that a kilobyte would be 1000 bytes. Actually, it means 1024 bytes. In the digital world kilo is 2 to the tenth power or 1024.
You may see sizes written as kB or KB. These are not the same. The lower case k denotes units of 1000 while an upper case K denotes units of 1024 .
Units of measure go from the kilobyte up:
1 kilobyte = 1000 bytes
1 megabyte = 1000 kilobytes
1 gigabyte = 1000 megabytes
1 terabyte = 1000 gigabytes
1 petabyte = 1000 terabytes
1 exabyte = 1000 petabytes
1 zettabyte = 1000 exabytes
1 yottabyte = 1000 zettabytes
The later few may not seem relevant right now. Certainly, in terms of computer memory or storage sizes, those are still measured in gigabytes or terabytes respectively. You do see dataset sizes expressed in the petabyte and exabyte ranges now.
For instance, in 2011 the size of the US Library of Congress was estimated to be about 10 terabytes  though that seems to have been a very conservative estimate. Looked at another way, it is estimated that 2.5 quintillion bytes (i.e. 2.5 exabytes) of new data is created each day . And another 2017 report says the US alone generates 2.657 petabytes of data per day .
What this means is that when we see reports on the size of data, the units of measure will constantly be getting bigger. You need to be prepared to understand the magnitudes being discussed.