Difference between megabits and megabytes and why it matters

Megabits and megabytes sound a lot alike, and they even have very similar abbreviations: Mb for megabits and MB for megabytes. But what are megabits and megabytes exactly? How do you convert megabits to megabytes? And why does understanding the difference between the two matter when selecting an internet plan?

Megabits vs. megabytes: What do they mean?

The answers are rooted in how computers work. At its heart, a computer consists of millions or even billions of tiny transistors. Each transistor only has two settings — on or off, like a teensy light switch. On is represented by a 1, and off is represented by a 0. A bit (binary digit) represents one of those transistor settings, with a value of 0 or 1. This same system can be applied to anything with two states similar to on and off, such as magnetic particle orientation (north-south or south-north) in a hard drive.

A byte is a collection of eight bits. This number was chosen because eight bits are enough to define 255 characters, which includes the entire alphabet in upper and lower case, all the numbers zero through nine, and quite a few special characters.

Of course, computers progressed rapidly beyond bits and bytes, so prefixes were added to deal with progressively larger numbers. Kilobits and kilobytes are 1,000 times larger than bits and bytes. Megabits and megabytes are 1,000 times larger than kilobits and kilobytes, and gigabits and gigabytes are 1,000 times larger than megabits and megabytes.

So, what is Mbps? Will a 100 Mbps connection download a 100 MB file in one second? Not exactly. In today’s internet age, connection speed is measured in Mbps, or megabits per second (and increasingly Gbps, or gigabits per second). Data is measured in MB, or megabytes.

Remember that a byte is equal to eight bits. Likewise, a megabyte is equal to eight megabits. So in the example above, the 100 MB file is actually 800 Mb, or megabits. Now it’s easy to see that a 100 Mbps (100 megabits per second) connection will actually download that file in eight seconds, not one second.

What is MBps? Nothing, actually. If internet connections were measured in megabytes instead of megabits, then you would see that designation. But they aren’t. Connections are measured in Mbps, meaning megabits rather than megabytes. Still confused? Let’s break it down further.

Megabits

  • Megabits are a common unit for internet speeds, expressed as Mbps or megabits per second.
  • A bit is the basic building block of computer storage, and a megabit equals one million bits.
  • Megabits measure data transfer speeds.
  • Internet service providers offer service tiers based on megabits per second, such as 100 Mbps or 300 Mbps (and increasingly gigabits per second, such as 1 Gbps)
  • Understanding Mbps is crucial to deciding which internet service is right for you.

Megabytes

  • Megabytes, or MB, are a common unit of data storage.
  • One byte equals eight bits, and one megabyte equals eight million bits.
  • Megabytes measure data. Every digital photo you take, or email you write or movie you stream takes up a certain amount of data space.
  • Megabytes (or gigabytes, which are 1,000 times larger) are used to define storage, such as hard drive space. They are also used by many internet service providers to set data caps.
  • If you’re buying a new computer, you need to know how many megabytes or gigabytes of storage it has. And when you’re shopping for an internet service provider, you need to know how many megabytes or gigabytes of data you are allowed to download or stream each month.

Why it’s important to know the difference between megabits and megabytes

Internet service providers (ISPs) list connection speeds in megabits per second (Mbps). But data is classified in megabytes (MB). If you’re not clear on the difference between megabits and megabytes, you might choose an internet speed that is too slow for your needs or overpay for more speed than you need. You might also misunderstand your monthly data cap, which could be very expensive since many ISPs charge a lot of money for data overages.

So how fast does your internet need to be? That depends on what you do online and how many people are sharing your connection. Standard video streaming takes about 3 Mbps. HD streaming and online gaming require about 5 Mbps each. YouTube streaming takes around 7 Mbps, and 4K streaming needs about 25 Mbps.

But this is only part of the story. The connection speed that comes into your home is then shared between all devices that are simultaneously connected. So if you have a 25 Mbps connection, you could theoretically have five devices all streaming HD video at the same time.

But in reality, streaming and gaming services try to preload to avoid buffering lag. This means that a 7 Mbps YouTube video could actually peak at around 250 Mbps on a fast connection. These services are also good at automatically downgrading video quality to run on slow connections, but it’s something to consider when deciding how much speed you need.

In addition, theoretical speeds are not necessarily actual speeds. The internet speed that enters your home is not necessarily as high as advertised, especially if you are using a wireless connection to your router.

Megabytes (or more often gigabytes) matter when considering data caps. If you watch five hours of movies in standard definition during the month, you will exceed 1 GB of data. It takes 170 hours of social media activity, or nearly 7,000 emails, to reach the 1 GB mark.

Why is it more common to use megabits vs. megabytes?

There’s no real reason for ISPs to list their speeds in megabits instead of megabytes, other than it’s the way it’s always been done. Chalk it up to an artifact of the early history of the internet. Fortunately, as long as you understand megabit vs. megabyte, this peculiarity should never trip you up.

The bottom line

Megabits and megabytes can be a bit confusing, which could lead you to choose an internet speed or data cap that doesn’t work for you. Just remember that a megabyte is eight times bigger than a megabit and that internet speeds are measured in megabits while data is measured in megabytes, and you should be able to decode all the information that your internet service provider has to offer.