Bits and bytes and broadband: Part One

Ever been confused by broadband speeds? In this two part blog I’m going to try and explain all.

Bits and Pieces

First let’s go over a few terms you’ve probably read or heard about:

  • Kilobits
  • Megabits
  • Gigabits
  • Kilobytes
  • Megabytes
  • Gigabytes
  • Megablobs (OK I made that one up….)

The first thing to say is don’t feel bad about not understanding these unit!

They are confusing, used only for historical reasons and are not even consistently used. Computer scientists, physicists, network & hard drive manufacturers might give you a different definition of some of these units.

This is not your fault, and in fact some companies will actively use this confusion against you.

So let’s try to unravel these units.

The basic units are reasonably easy:

  • A bit is a zero or one

A “bit” is the smallest unit of information in computing. It’s basically a “0” or a “1”, or if you like a “yes” or a “no”. It might sound strange that the whole basis of modern technology is built on so humble a thing, but the reason is because of  the way electronic hardware (i.e . your computer) works. The point is that if you string together enough “yes” and “no’s” you can represent anything (imagine a game of 20 questions, only you have a million goes!).

  • A byte is 8 bits

A “byte” is 8 lots of bits in a row. A byte is roughly enough information to represent a single character of the English language. So “hello” would be 5 bytes (which is 40 bits (5 x 8)).

(I’m glossing over two issues: firstly older computer systems might use different numbers of bits to refer to a “byte” e.g. 6, 7, 8 or 9 bits. Nowadays, it’s almost universally 8 bits. Secondly, characters in other languages might require 2 or more bytes to store).

  • A kilobit is 1000 bits.
  • A kilobyte  is 1000 bytes.

So those are easy. Maths nerds reading this will realise  that a kilobyte is 8 times larger than a kilobit. That’s a commonly repeated pattern you’ll see between “bits” and “bytes”.

(So actually I’m lying here, again. SOME people (Computer Scientists in particular)  actually call a kilobyte 1024 bytes. The reasons for this are highly technical and really just to make life easier for Computer Scientists – thanks guys!

Recently there was a move to try to standardise the “kilobyte” to be 1000 bytes, but the problem is that lots of people still use the old size. You’ll see this issue repeated for Megabytes and Gigabytes – some people say a Megabyte is 1000 kilobytes, others say it is 1024 kilobytes. Read more about it here.

For most cases, the difference is quite small, so don’t worry about it too much.)

For those of you who remember studying the solar system at school, here is a familiar to-scale representation of the sizes of these units:

Relatively speaking, these units (up to the Kilobyte) are still very small. By comparison, a typical JPEG photo would be at least 200 kilobytes.

The next step up is the Megabit and Megabyte.

  • A megabit is 1000 kilobits
  • A megabyte is 1000 kilobytes

And here they are in comparison:

And finally we get to Gigabit and Gigabyte.

  • A Gigabit is 1000 Megabits
  • A Gigabyte is 1000 Megabytes

You can also see the relative size of a typical MP3 and a moderately high quality photo (JPEG).

Note how “kilobits” and “kilobytes” are so small, they don’t even appear on this chart. For modern day computing, the only unit of any useful size is Megabits/Megabytes, and Gigabits/Gigabytes.

That massive orange Jupiter-like blob in the corner is a Gigabyte. A modern decent sized hard drive would be at least 200 Gigabytes so you can imagine how big that would be.

Shortened Names

You’ll often see these units shortened like this:

  • kbps
  • mbps

The first two letters “kb” refer to the unit (kilobits, kilobytes, megabits, megabytes). “ps” stands for “per second”. So, it’s a measurement of how much data can be transferred in 1 second.

Unfortunately, these abbreviations are often used inconsistently, and not clearly.

One issue is how to distinguish between “kilobits” and “bytes”.

Often the convention is to use UPPERCASE “B” to refer to bytes and lowercase “b” to mean bits.

So:

  • KBps means kilobytes per second
  • kbps means kilobits per second
  • MBps means megabytes per second
  • mbps means megabits per second

BUT this  is often not consistently used, particularly in some companies’ marketing material. The rule of thumb is this: if it’s a broadband company talking about internet speeds, they will be referring to megabits and kilobits regardless of whether they use upper or lowercase letters for “mbps”.

Conclusion

  • A bit is the smallest unit of information: a zero or a 1
  • There are 8 bits in a byte
  • Common pattern of each unit is that it’s 1000 times larger than the previous unit (kilo –> mega –> giga)
  • Kilobits/Megabits are 8 times smaller than kilobytes/megabytes
  • Beware of abbreviations: kbps, mbps

In part two I’ll be talking about some of the pitfalls in the way broadband companies report speeds.

Broadband speed is relevant to our product, BuddyBackup, as it determines how quickly you can backup and restore files over the internet.

John Wood

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11 Responses to “Bits and bytes and broadband: Part One”

  1. Outdoor Water Fountain Says:

    Nice site, thanks for the information, i enjoyed the read

  2. Fernando Says:

    This is great! I don’t have to explain people this over and over… I don’t understand why people can’t differentiate between MB and mb… anyways this article describes that in details =)

  3. Bryan Says:

    M is the SI prefix for mega (100,000), m is the SI prefix for milli (1/1000th), so 1mbps would be one bit every 1000 seconds.

    Please don’t use m when you mean mega! (-:

  4. Torrent News » How Can I Make Sure I’m Getting the Download Speeds I’m Paying For? [Ask Lifehacker] Says:

    […] If you need a quick primer on what to look for, your connection speed will usually be something like, “Download speeds up to 20 Mbps and uploads up to 4 Mbps.” Mbps means Megabit per second and refers to transfer speed. (Don’t confuse Mbps with MBps, aka Megabytes per second. A MB is equal to 8 Megabits combined). Head over to Buddy Backup blog for a nice and simple breakdown of broadband speed terminology. […]

  5. How Can I Make Sure I’m Getting the Download Speeds I’m Paying For? [Ask Lifehacker] Says:

    […] If you need a quick primer on what to look for, your connection speed will usually be something like, “Download speeds up to 20 Mbps and uploads up to 4 Mbps.” Mbps means Megabit per second and refers to transfer speed. (Don’t confuse Mbps with MBps, aka Megabytes per second. A MB is equal to 8 Megabits combined). Head over to Buddy Backup blog for a nice and simple breakdown of broadband speed terminology. […]

  6. RomelSan Says:

    Nice Info, Thanks

  7. Tariq Says:

    My internet provider claims to give a connection of 2 megaBYTES per second.. Is this possible or could it be that they are misleading me?

    • Bryan Says:

      2 MB/s (megabytes/sec) is 16 Mb/s (megabits/sec) which is perfectly possible, there are people getting 40 Mb/s (which is 5 MB/s) or even 100 Mb/s.

      It is very unusual to measure connection speeds in MB/s though, so it is quite possibly a mistake or typing error.

  8. byte to megabyte converter Says:

    Do you mind if I quote a few of your posts as
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  9. outlier Says:

    Very nicely explained in simple terms for people unfamiliar with the terminology. Great Job !!

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