Gigabyte (GB) vs. Megabyte (MB): Size And Difference Explained


Gigabyte (GB) vs. Megabyte (MB): Size And Difference Explained

On your smartphone, your laptop, your tablet, or your video game console, you’ve undoubtedly encountered the words gigabyte (GB) and megabyte (MB) before. You may or may not know that a gigabyte is bigger than a megabyte, but do you know exactly how much bigger? Likewise, do you know the difference between decimal and binary notations for each? It’s not a problem if you don’t — this guide will compare gigabyte (GB) vs. megabyte (MB) to help you understand the difference in size and purpose for each unit of information in computing.

Gigabyte (GB) vs. Megabyte (MB): Side-By-Side Comparison

Bytes1,073,741,824 bytes1,048,576 bytes
Gigabytes1 gigabyte1/1024th of a gigabyte
SymbolsGB, GiBMB, MiB
Followed ByTerabyteGigabyte

Gigabyte (GB) vs. Megabyte (MB): What’s the Difference?

The side-by-side comparison above does a nice job of elaborating on some of the basic differences between gigabyte (GB) vs. megabyte (MB). However, there’s more to each unit of information than just numbers and letters. Let’s spend some time explaining each unit to better understand what sets them apart.

Gigabyte Explained

Based on what we’ve learned in the side-by-side comparison, it’s clear to see that the gigabyte is a whole lot bigger than the megabyte — over a thousand times bigger, in fact. A single gigabyte contains exactly 1,024 megabytes. (That’s over a billion bytes in all.) A gigabyte is a step below a terabyte, which in turn represents 1,024 gigabytes. The scale keeps going up and up like this until we reach the yottabyte, which represents a near-unfathomable quadrillion gigabytes. Following that math, that’s a million trillion megabytes. Needless to say, no average joe will ever need this kind of storage.

As with most units of information in computing, there are a couple of different ways to describe the number of bytes in a gigabyte. First, we have binary notation, and then we have decimal notation. In binary notation, the gigabyte is equivalent to 1,073,741,824 bytes. In decimal notation, it is reduced to a simple billion bytes. The difference between the two is a not-insignificant 73,741,824 bytes, or 73 megabytes. To distinguish the two, the binary notation version is dubbed “GiB” while the decimal notation version retains the abbreviation “GB.”

In the early years of computing — much of the first 40 years of computing technology, to be specific — there was no need for anything larger than the megabyte. Storage space on the computer was limited because computing power itself was limited. However, as time went on, there became a clear need for a larger unit of storage. Thus, after decades of technological innovation, IBM became the first to release a one-gigabyte hard drive in the year 1980. The rest, as they say, was history. There was no need for a larger storage unit until the establishment of the terabyte in the late 1990s and early 2000s.

IBM PC Model 5150.
The IBM 5161 Expansion Chassis for the PC Model 5150 came with one 10MB hard disk.

Megabyte Explained

As we’ve been able to tell so far, the gigabyte and the megabyte are pretty closely related. Nevertheless, the megabyte remains the smaller of the two by a significant margin. One single megabyte is worth just one-thousandth of one gigabyte. (That’s a fraction of a fraction of a percent.) Though the two units of information are just a step away from one another on the scale, the so-called step is much closer in spirit to a leap. Typically seen abbreviated as MB or MiB, the megabyte remains one of the most commonly used units of information in computing because of its mid-range size.

Judging by the aforementioned abbreviations, it’s clear that decimal and binary notations are not exclusive to the gigabyte alone. The megabyte’s decimal notation is equivalent to a million bytes. The binary notation for the gigabyte, increases that number to a very specific 1,048,576 bytes. And, also like the gigabyte, there is a binary notation-specific name for the megabyte. It’s “mebibyte.” Though both megabyte and mebibyte are used interchangeably in spite of their unique definitions, there is an increasingly large push to more clearly distinguish the two in the computing industry.

In addition to the distinction between gigabyte and megabyte, there’s also a distinction to be made between megabyte and megabit. (This latter unit is characterized by the abbreviation “Mb” rather than “MB.”) Here’s what sets them apart: “MB” is a unit of information, while “Mb” is a unit of speed that the information (or bit) travels at. On a scale, a single megabyte would equal eight megabits. However, it’s important to reiterate that bytes are a measurement of size whereas a bit is a measurement of speed. In other words, one is for storage and the other is for networking.

Gigabyte: Real-World Examples

In order to more definitively establish what a gigabyte actually looks like in the real world, let’s take a look at some scenarios where you might encounter them in your daily life.


Every time you insert a game into your console or download one to your PC, you’re using up a certain amount of gigabytes in storage. The average Nintendo Switch game comes in at around 30 GB or less, whereas your average PlayStation 5 game comes in at around 100-200 GB. Surprisingly, some PC games exceed 200 GB or more in total size. You’ll also notice different GB sizes for physical games vs. digital games — the former tends to be smaller than the latter.

Nintendo Switch - playing game
Animal Crossing for Nintendo Switch is approximately 7GB.

Home Video

Another place you’re likely to encounter gigabytes? Home video formats. There’s a big difference in total GB between DVDs and Blu-rays. A DVD holds anywhere from 4 to 8 GB, while a Blu-ray can hold anywhere from 25 to 50 GB. 4K UHD discs can hold as much as 100 GB. This difference in sizing does a nice job of illustrating how storage standards have evolved over time. With DVDs in the early 2000s, 4-8 GB was more than enough. Today, a 4K UHD disc’s 100 GB is much more useful.

Megabyte: Real-World Examples

Now that we have a good handle on how gigabytes factor into the world around us, it’s worth doing the same for megabytes. The following are some real-world examples of a megabyte’s true size.

Digital Files

No matter if your preferred device is a tablet, a smartphone, or a computer, you’re going to see lots of different files stored in megabytes. From a photo to a video to a PDF to an audio file, megabytes are the standard unit of information used to define the size of your digital files. While some videos might stretch into the gigabyte range, shorter videos shot on your phone, laptop, or tablet will probably come in around a few hundred MBs. Your typical candid photo might measure around 4 MB.

Gigabyte vs. Megabyte
This candid photo shot on an iPhone 12 Pro Max is 1.25MB

Cellular Data

Another real-world scenario where megabytes are used quite regularly? Mobile data. Whether you’re browsing the internet, watching a video, listening to a podcast, or texting photos, you’re going to use up dozens of MB of mobile data with each action. Listening to the latest album from your favorite artist on Spotify? Probably around 50 to 100 MB. Watching a 10-minute video on YouTube? Right around 100 MB, as well.

Frequently Asked Questions

How big is a megabyte?

A megabyte is approximately one million bytes, or a thousand kilobytes. Furthermore, it’s around one thousandth of a gigabyte.

How big is a gigabyte?

A gigabyte is equivalent to a thousand megabytes, approximately. This pans out to a billion bytes, or one million kilobytes. Additionally, it makes up one thousandth of a terabyte.

What is the smallest unit of information in computing?

The bit is the smallest unit of information in computing, representing a single binary digit equivalent to either one (1) or zero (0). A byte is made up of eight bits, making it the second-smallest unit of information in computing. (Unless you count a nibble or a crumb, which are fractional bytes.)

What is the biggest unit of information in computing?

A yottabyte is the largest unit of information currently standardized. It represents a septillion bytes, which is equivalent to a million trillion megabytes or a quadrillion gigabytes.

How many megabytes are in a gigabyte?

There are 1,024 megabytes in a gigabyte. (Unless you’re dealing with decimal notation, in which case there are 1,000 megabytes in a gigabyte.)

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