*How big is a gigabyte? What is a terabyte? Have you ever needed a petabyte? Let’s explore more about memory storage size.*

You may also know that a terabyte is greater than a gigabyte. But if you are not familiar with computers, these are all abstract terms. While you can visualize an inch or a liter, it is much more difficult to imagine a terabyte or a petabyte.

To put it in perspective, let’s look at computer storage sizes to see how big a gigabyte, a terabyte, and more can be.

**Byte Basics Explained**

If you’re not familiar, let’s first review the basics of computer storage.

A bit is the smallest amount of data a computer can store. Since computers use a binary numbering system, each bit can be either 0 or 1. To put this in perspective, one bit is enough to store whether a value is true or false. For example, in a video game, a bit can be 1 if the player has earned a certain upgrade and 0 if they haven’t.

Eight bits together are called bytes, which are the building blocks of total storage. One byte can contain 256 possible values. For example, storing a single character in the ASCII encoding standard.

**Kilobytes and Megabytes**

Like most measurements, as size increases, prefixes are used to denote larger amounts of data.

A kilobyte (KB) , the first major grouping, equals 1,000 bytes. You will recognize the prefix “kilo”, as it is used in other thousand measurements, such as “kilometer” (1,000 meters). To get an idea, a text file containing about 1,000 characters equals roughly one kilobyte.

The final measure before we reach the larger denominations is **one megabyte (MB)**, which is 1,000 kilobytes (or one million bytes). One megabyte holds approximately one minute of music in MP3 format. As a bit of another perspective, a standard CD holds around 700MB. Keep in mind that a megabyte is different from a megabit.

Before we continue, we should mention the difference between how computers and humans measure storage. Due to the way the binary system works, one kilobyte is actually equal to 1,024 bytes, not 1,000. That variety grows as you climb the size ladder, which is much more noticeable at higher storage amounts. This is why a 250GB hard drive only displays about 232GB available.

Since the correct definition of a prefix like “giga” is an even multiple of 1,000, for simplicity we’ve used the power of 1,000 instead of 1,024 here. Other prefixes, such as “kibi” and “gibi”, correctly represent multiples of 1,024. See our full explanation of the different computer size formats for more details.

**How Big is a Gigabyte?**

You are probably familiar with the term gigabyte (GB) as it is the most common storage unit for today’s devices . If you’re wondering how many bytes are in a gigabyte, remember that each level increases by a multiple of 1,000.

We’ve seen that there are 1,000 bytes in a kilobyte and 1,000 kilobytes in a megabyte. Because one gigabyte equals 1,000 megabytes, one gigabyte equals 1 billion bytes.

In perspective, 1GB holds about 230 standard MP3 tracks. Depending on the video codec used, approximately three minutes of 4K video at 30FPS equals 1GB. And a standard DVD holds about 4.7GB.

Most of today’s smartphones come with between 32GB and 512GB of storage. However, computer storage drives are available in much larger sizes, which brings us to the next unit …

**How many Terabytes?**

You can buy internal and external hard drives and SSDs available in terabyte denominations now. But how big is a terabyte in comparison?

Keep in mind that moving to a terabyte (TB) only increases its value by another 1,000 power. So, there are 1,000 gigabytes in a terabyte, and a terabyte equals a trillion bytes.

I mentioned earlier that a basic CD holds around 700MB and a DVD holds around 4.7GB. That’s why you need almost 1,430 CDs or 213 DVDs to get a terabyte of storage!

For example, a common estimate is that the average book takes about 1MB to store (excluding illustrations). In late 2019, Google announced that Google Books had scanned over 40 million titles. This means you need around 40TB to store all the books on Google Books.

**What is a Petabyte?**

This is the first data size you may not know about. One petabyte (PB) is equal to 1,000 terabytes, or one quadrillion bytes. This is a staggering amount of information that is difficult to comprehend.

To try to put this in perspective, scientists estimate the human brain has about 2.5PB of memory space. 1PB will be enough to store 24/7 video footage at 1080p for almost 3.5 years. You can take 4,000 digital photos every day for the rest of your life to fill one petabyte too. And as of March 2018, AT&T transfers 197PB of data over its network every day.

In other words, the Milky Way Galaxy is home to about 200 billion stars. If each star were one byte, we would need 5,000 Milky Way galaxies to reach 1PB of data.

**Exabytes, Zettabytes, and Yottabytes**

On top of petabytes, there are still some larger amounts of data storage. We’ll take a look at it briefly so you get used to it, but it’s so large that you’re unlikely to hear it referenced in normal conversation for years to come.

An **exabyte (EB)** is 1,000 petabytes, or one trillion bytes. 2004 was the first time that worldwide monthly internet traffic passed 1EB. In 2017, the internet handled around 122EB of data every month. You can fit around 11 million 4K movies in one exabyte of storage.

Next is **zettabyte (ZB),**Ã‚ which is equivalent to 1,000 exabytes or one sextillion bytes. The International Data Corporation calculated that the global data world was about 33 zettabytes in 2018. As another way of looking at it, the Australian continent is about 2.97 million square miles. If each square mile represents one terabyte, you can fit nearly 337 Australian copies into one zettabyte.

The largest data size currently defined is **yottabyte (YB).**Ã‚ This staggering unit equals 1,000 zettabytes, or one septillion bytes. Comparison with current data sizes is a bit ridiculous, but it’s estimated that you can fit 257.054 trillion DVDs or 288.230 quadrillion MP3 songs on average in one yottabyte.

__Gigabytes, Terabytes, Other Sizes: Described!__

It’s amazing to consider how far storage technology has come in just a few decades. We can now store huge collections of video, audio, image and other data on our computers and phones that was unthinkable 20 years ago.

It may be a while before you can buy a storage drive measured in petabytes or larger, but now you know roughly how much these units can store.