As the average size of files and computer storage has grown over the decades, we are using more terms than ever to represent file sizes.

You may have heard terms like kilobyte, megabyte, gigabyte and terabyte thrown around, but what do these actually mean?

More importantly, how do these relate to each other, and which ones are the biggest?

In this article, I’ll cover everything that you need to know!

Which is Bigger – A Kilobyte (KB), Megabyte (MB), or Gigabyte (GB)?

Person Using Laptop Computer

The three most common data measurement units that you’ll hear these days are:

  1. Kilobytes, often abbreviated to KB or kb.
  2. Megabytes, often abbreviated to MB or mb.
  3. Gigabytes, often abbreviated to GB or gb.

There’s also a fourth one that’s becoming more common for everyday computing, called terabytes, which is often abbreviated to TB or tb.

So, which one is the biggest?

Terabytes are the largest you’ll commonly hear used, followed by gigabytes, megabytes, then kilobytes.

All of these follow a similar format:

1 terabyte is equal to 1,024 gigabytes.

1 gigabyte is equal to 1,024 megabytes.

1 megabyte is equal to 1,024 kilobytes.

Why 1,024, and not 1,000 you ask? It comes down to the way that computers work.

Computers use a binary system, and therefore are measured in the power of 2:

2, 4, 8, 16, 32, 64, 128, 256, 512, 1024

This is partly why you see these numbers appear so frequently in other areas of computing as well!

File Size Measurements In Order

Kilobytes, megabytes, gigabytes and terabytes are not the only units used for measuring data storage! In fact, computers go far beyond this in both directions, with larger and smaller units often being used.

Let’s look briefly at each one of these in order.

Bits are the smallest unit of measurement.

1 byte = 8 bits.

1 kilobyte = 1024 bytes.

1 megabyte = 1024 kilobytes.

1 gigabyte = 1024 megabytes.

1 terabyte = 1024 gigabytes.

1 petabyte = 1024 terabytes.

1 exabyte = 1024 petabytes.

1 zettabyte = 1024 exabytes.

1 yottabyte = 1024 zettabytes.

While there are other units that have been named, there is not currently anything that comes close to a yottabyte yet.

In fact, even all of the world’s data combined together (including private data, like security camera footage, the contents of everyone’s photos and computer files, etc.) does not come close to reaching a yottabyte.

So, measuring anything beyond that is a little pointless at the moment!

Understanding Bytes

Although we’ve looked up to extreme data sizes, let’s take things backwards a little bit, and look at the smallest units of measure – bits.

All computers work in binary, which can only have two values – 0, or 1. Each 0 or 1 is considered a bit of information.

A single letter is made up of 1 byte, and 1 byte is made up of 8 bits.

Take the letter C for example. In binary, the letter C is 01000011.

As you can see, there are 8 numbers there, with each one representing 1 bit.

Bits and bytes are incredibly small units of measurement in modern computing. The average photo taken with a smartphone can end up being around 5 megabytes. This can end up being 5 million bytes, or 40 million bits of data.

So, having larger units of measurement, like kb, mb and gb really come in handy!


When it comes to file measurements, 1 gb is greater than 1 mb, and 1 mb is greater than 1 kb.

Other than bits, the pattern is always the same. 1024 of one unit forms one of a larger unit. For example, 1 gigabyte is equal to 1024 megabytes.

I hope that you’ve found this article helpful. If you have any other questions about data storage (or units of measurement as it relates to data), please ask them using the comment form below.

Wishing you the best,

– James McAllister

About the author 

James McAllister

James is the owner of He started his first blog at the age of 11, and has since gone on to start several successful businesses. In total, these businesses have sold hundreds of thousands of units and have touched millions of lives. Here on, he shares his knowledge that brought him to where he is today. If you want to connect with James, follow him on your favorite social networks!

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  1. Hi James, I've been a care taker for my mom several years , and unfortunately lost her few months ago. When your in

    your early 60's trying to get back on your feet its hard! I lost touch with almost everything , the little knowledge I had is

    outdated and have to learn everything from scratch. Fortunately though, I have not lost my quest to learn and never

    give-up until I master it. Many of my family members rely on me for most of their computer work, and that is also another

    reason that drives me to learn and get better. Of late I had to downsize files , struggled and through trial and error

    made it, but decided to understand this whole binary system and how it works. I can't thank you enough for your article

    on File size and measurements, was simply put, and easy to understand. Thank you once again!


    1. Hi Iris! Thank you so much for taking the time to write out this kind and thoughtful comment. I am so glad that the article was able to help you, and if you ever have any other tech-related questions please don’t hesitate to reach out!


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