Megabits vs. Megabytes: Here’s How They’re Different
There are 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 capitalized “b” in the latter term.
Unsurprisingly, the two terms get mixed up all the time. Even people who understand them perfectly can bungle the two with a slip of the tongue or typing the wrong “b.”
We’ll explain what the difference is so you can keep them straight when it really counts.
Bits vs. bytes: What is the difference?
The term bit is short for binary digit, and it’s the smallest unit of data. The value is either a “1” or a “0” although the value can signify “on” and “off” states or something similar.
The term byte is a group of 8 bits. This term is also used to describe the smallest unit of memory and storage.
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 does Mbps mean?
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.
What are bits and bytes used for?
We tend to use the terms “bits” and “bytes” in different settings. Both terms describe a measurement in size, but the term “bit” is also used to measure speed.
In terms of memory, a byte is the smallest storage slot. Your hard drives, SSDs, USB sticks, and system memory are always measured in bytes.
Software is measured in bytes too. A single byte is 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 used to determine your internet speed, but measuring data in motion (downloading and streaming) is trickier than measuring data at rest (files, programs, etc.).
For instance, 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 that must 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.
When someone talks about data transfer rates, upload speeds, download speeds, or bandwidth, they’re probably measuring it in bits per second (bps).
Megabits vs. megabytes: 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.
Megabits vs. megabytes: 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 still defines “kilobyte” as 1,024 bytes (220) and “megabyte” as 1,024 kilobytes, although the proper terms are “kibibyte” and “gibibyte.”
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?
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Author - Peter Christiansen
Peter Christiansen writes about satellite internet, rural connectivity, livestreaming, and parental controls for HighSpeedInternet.com. Peter holds a PhD in communication from the University of Utah and has been working in tech for over 15 years 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 been editing and writing in the digital space for seven years, and she's edited all things internet for HighSpeedInternet.com for five years. She graduated with a BA in English and a minor in editing from Brigham Young University. When she's not editing, she makes tech accessible through her freelance writing for brands like Pluralsight. She believes no one should feel lost in internet land and that a good internet connection significantly extends your life span.