Megabits and Megabytes: What’s the Difference?

How is one bit different than one byte? Why is bandwidth and download speed measured in megabits while data is measured in megabytes? What’s the difference, and why should you care?

The difference in speed scales is mainly technical, but it has a bearing when making broadband buying decisions. Internet speeds usually get advertised in megabits per second (Mbps), so it pays to know what the term means and how much data one megabit contains. Understanding Mbps helps you make an informed decision when shopping for internet service and for calculating what speed you need based on your typical uses.

Comparing Megabits and Megabytes

Here are the bare essentials of what you should know:

• A megabit is used to measure download and upload speeds.
• A megabyte is used to measure file size. The measurement is the same, whether you refer to storage devices or file transfers.
• Megabits are advertised as Mbps.
• Megabytes are advertised as MBps.

Those last two points are quite important as they mean very different things. To confuse matters more, a megabit and a megabyte are not the same size. One megabyte contains eight megabits. Google has a helpful Mbps and MBps converter tool to make calculations simple.

If a broadband package speed is advertised as 24Mbps, that does not mean you can download a 24 MB (megabytes) file in one second. It will take 8 seconds as there are eight megabits per megabyte. So without going into too much math, downloading a file described in megabytes needs multiplied by 8 to determine how long it will take to download.

Why We Use Megabits and Megabytes Instead of One Measurement

Why can’t companies use just megabytes to describe both speed and size? The simple answer is that the two areas of technology evolved separately, and both are so entrenched in their way of doing things that it is almost impossible to change. It has nothing to do with the ISPs but the relative areas of the appropriate industries.

In comparison to Mbps and MBps, most of the world uses the metric system for size measurements. Still, The US uses the Society of Automotive Engineers (S.A.E.) scale, also known as SAE, in addition to the metric (meters) system even though metric is the industry’s universal standard. In this situation, the SAE industry is set in their ways, just like the Mbps and MBps controversy.

Aside from different industries, the Mbps measurement scale makes things seem faster than they really are. Gas prices in the U.S. add a third integer to make things look cheaper, such as $2.099 instead of $2.10. A fiber-optic internet package at 50 Mbps sounds much faster than 6.25 MBps, which is what the transfer speed “actually” is when measured in megabytes instead of megabits per second.

Internet Service Providers use Mbps rather than MBps

Fortunately, the only time you really need to know the difference between a megabit and a megabyte is when you are shopping for a new broadband package. The vast majority of Internet Service Providers (ISPs) will advertise their speeds in Mbps, which is the megabits per second measurement.

The “Need for Speed” Motivates Mbps Advertising

If you are a heavy internet user, faster speeds are more desirable. Therefore, the Mbps system sounds better than the MBps system. It is best to get as fast a connection as possible in your area within your given budget, but be sure to calculate the provider’s true speed potential by converting to Mbps to MBps speeds.

Here are a few examples of broadband types and the maximum speeds they advertise.

• Digital Subscriber Line (DSL) connections allow up to 45 Mbps.
• Cable connections allow up to 2000 Mbps.
• Fiber-optic connections allow up to 940 Mbps.

The speeds above are for reference only, and you are not guaranteed to get those measurements. However, it illustrates the difference between DSL, cable internet, and fiber-optic internet using the industry-standard Mbps.

Translating the above internet speeds from Mbps to MBps, you get the following calculations:

• DSL at 45 Mbps converts to just 5.625 MBps, which is under 6 megabytes per second
• Cable internet at 2000 Mbps converts to 250 MBps.
• Fiber-optic internet at 940 Mbps converts to 117.5 MBps, which is almost 118 megabytes per second.

Hopefully, now you have a much better idea of the difference between megabits and megabytes. Sorry for all the math, but it is impossible to explain how this all works without it! Surprisingly, most people never noticed or recognized that the internet provider’s measurements are different from hard drive read and write speeds.