Megabits vs. Megabytes: Here’s How They’re Different
You run across a lot of confusing technical terms when working with computers and the internet, but few are as needlessly ambiguous as the difference between megabits per second (Mbps) and megabytes per second (MBps). The two terms sound almost identical when spoken and are abbreviated with the exact same letters: the only difference is the b is capitalized in the latter.
Unsurprisingly, people get them mixed up all the time. Even people who understand them perfectly can bungle the two with a slip of the tongue.
We’ll explain what the difference is so you can keep them straight when it really counts.
Bits vs. bytes
Bits and bytes are both units of data, but bytes are bigger. Every byte is made up of eight bits. This also means that any measurement written in bytes is eight times larger than the corresponding unit measured in bits. In other words, 1 megabyte (1 MB) = 8 megabits (8 Mb). And 1 gigabyte (1 GB) = 8 gigabits (8 Gb). With us so far?
What they’re used for
So, if bits and bytes are both metric units, why do we have these weird groups of eight making our math more complicated? Well, we tend to use each one in different settings.
A byte is the smallest unit of addressable memory in a computer, or, in other words, the smallest slot that the computer can point to. Your hard drives, your RAM, your files—all of these are measured in bytes. This slot is also just big enough to store the data for one standard character, so storing the word “hello” would need five bytes of memory, one for each letter. This is why computer memory is generally measured in bytes.
A bit is a single binary digit—a one or a zero; on or off. It’s the very smallest unit of information used in digital devices. It’s also the measurement used to determine how fast your internet connection is. But data moving on the internet is a bit more tricky. The websites you visit and the emails you send are broken up into packets and sent in several different directions, often arriving at your computer out of order and have to be rearranged. This erratic flow of data isn’t always easy to divide into bytes, so the speed at which data moves is usually measured using bits per second. If someone is talking about data transfer rates, upload speeds, download speeds, or bandwidth, they’re probably going to be measuring it in bits per second (bps).
What’s a Mbps?
Bits per second (bps) is the number of bits that can move between two devices in a single second. When talking about internet speed, this is the number of bits that arrive on your machine every second. It’s also sometimes called your download speed or your bandwidth.
Bits per second can also have metric prefixes. One kilobit per second (kbps) is 1,000 bps, one megabit per second (Mbps) is 1,000,000 bits per second, and one gigabit per second (Gbps) is 1,000,000,000 bits per second.
You could technically measure speed in bytes per second as well, simply by taking the speed in bits per second and dividing by eight. However, speed is almost never measured in bytes, so if you see a speed listed for an internet connection, it’s safe to say that it’s using bits per second.
Why it matters
These subtle differences in units make it easy to flub your math when dealing with your internet speed. If you happen to get them mixed up, your calculations will be off. Way off.
For example, let’s say you want to download a 500 MB file, and you have a 100 Mbps internet connection. If you don’t notice the capital B in the file size, you might estimate that this download would take five seconds. However, the units don’t match up. The file size is measured in megabytes, while the connection speed is measured in megabits per second. Since the file size is eight times larger than you originally estimated, it actually takes eight times as long to download—40 seconds.
Now, waiting 35 seconds longer than you expected isn’t too bad, but waiting an extra 35 minutes on a download that was supposed to take only five is more of an inconvenience. This can also be frustrating if you realize you’re paying for an internet connection that gives you a lot less speed than you thought.
Why it doesn’t matter
If you’re having trouble keeping track of all these numbers, relax. Take a deep breath, and get yourself a snack. While it’s important to know the difference between bits and bytes (and to know that there is a difference), you don’t have to worry about making an expensive blunder.
First, bits and bytes are used in different contexts. Generally speaking, speed always uses bits and storage capacity always uses bytes. If you’re buying a hard drive, all the brands you’re comparing will be using bytes. If you’re looking for an internet provider, all the speeds will use bits.
You never have to worry about converting between units. Even if a provider wanted to be sneaky and measure its speed in MBps instead of the standard Mbps, it would only make their connection look eight times slower than it actually is.
Second, you’ll likely never have a practical need to calculate exact download times. When you do download a large file, any modern browser will calculate the download time for you automatically. But even these exact calculations are rarely spot-on because there are so many other factors that impact how long it takes your data packets to download.
Even the exact size of a megabyte isn’t always exact. For example, Microsoft Windows actually defines a kilobyte as 1,024 bytes (220) and a megabyte as 1,024 kilobytes.
The important thing to know about your internet speed is not what volume of data it could download in an ideal situation, but whether or not it’s fast enough to do what you want it to do. Is it fast enough to stream HD video? Is it fast enough to play online games? Is it fast enough to work from home?
Author - Peter Christiansen
Peter Christiansen holds a PhD in Communication from the University of Utah and has been working in tech for over 15 years, working as a computer programmer, game developer, filmmaker, and writer. His writing has been praised by outlets like Wired, Digital Humanities Now, and the New Statesman.
Editor - Cara Haynes
Cara Haynes has edited for HighSpeedInternet.com for three years, working with smart writers to revise everything from internet reviews to reports on your state’s favorite Netflix show. She believes no one should feel lost in internet land and that a good internet connection significantly extends your life span (buffering kills). With a degree in English and editing and five years working with online content, it’s safe to say she likes words on the internet. She is most likely to be seen wearing Birkenstocks and hanging out with a bouncy goldendoodle named Dobby, who is a literal fur angel sent to Earth.