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Bits and bytes: know the difference

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Knowing your bits from your bytes is useful for picking out a good broadband provider – here’s the important info.

What are bits and bytes?

Bits and bytes are different units of measurement, though you’re likely to have come across both while using the internet.

  • Bits are usually used to measure connection speed, normally in the form of megabits
  • Bytes are usually used for measuring the size of data, often as megabytes or gigabytes

The differences between bits and bites

There are other things factors separate bits and bytes – they might sound like similar quantities but a byte is eight times bigger than a bit, so you can say that one byte contains eight bits of data. This therefore means a megabyte is eight times bigger than a megabit, and so on.

They’re also represented different when you read or write about them:

  • Bits are given in a lower case ‘b’ – so a megabit is Mb
  • Bytes are given in an upper case ‘B’ – so a megabyte is MB.
Bits and bytes explained

Bits, bytes, and broadband

Though bits and bytes are used to measure different things, you can use both to understand how your broadband will work - by knowing your connection speed and the size of a file online, you can make a rough guess about how long it will take to download the file.

For example, if you want to download a file of 150 megabytes and you know your connection speed is 25 megabits per second:

  1. You know it will take six seconds to transfer 150 megabits (Mb)
  2. It will then take eight times that amount to download 150 megabytes (MB)
  3. It should therefore take, if your connection speed remains perfect throughout, roughly 48 seconds to download the file.

However connection speeds aren’t always perfect, and there are a number of things that can interfere with your broadband - learn more with our guide to broadband speed.

Broadband deals and speeds: What should I look for?

Broadband speeds are advertised in bits per second, or bps. Simply, that’s how many bits the connection can download in a second. The more bits per second it can download, the faster the speed.

Of course, these days you tend to see it measured in megabits per second (Mbps) or gigabits per second (Gbps).

And remember that one bit (1b) is eight bytes (8B). A 10Mbps connection would in fact take eight seconds to download a 10MB file.

Let’s look a bit closer at what broadband speeds really mean, though. Ofcom rules around advertising stipulate that broadband providers must advertise the average speed that at least 50% of people on that package can achieve with their connection, with a guaranteed minimum speed.

For example, a “76Mbps” package means that at least half of users on that service can download an average of 76 megabits of data per second. For your property or postcode, the provider may guarantee a minimum speed of 50Mbps on that package – meaning you should be able to download at that speed at all times.

And these are just the download speeds. That’s how much data can be transferred from the internet exchange to your router per second. You’ll also see upload speeds mentioned – in other words, how much data can be transferred from your router to the exchange per second. Usually, upload speeds are a fair bit lower than download speeds, because most of us download a lot more data than we upload.

Read more about what broadband speeds mean here. And see what speed you're getting right now with our broadband speed test.

So what are KB, MB, GB, and TB?

We use an awful lot of data these days, and bits and bytes simply aren’t big enough to measure it.

So, you’ll also see kilobytes (KB), megabytes (MB), gigabytes (GB), and terabytes (TB) – and kilobits (Kb), megabits (Mb), and gigabits (Gb).

  • 1KB is 1,024 bytes
  • 1MB is 1,024KB
  • 1GB is 1,024MB
  • 1TB is 1,024GB


  • 1Kb is 1,024 bits
  • 1Mb is 1,024Kb
  • 1Gb is 1,024Mb
  • 1Tb is 1,024Gb

Again, you’ll normally see KB, MB, GB, and TB used to measure file sizes and storage in digital devices, while Mb and Gb are used to measure broadband speed.

You won’t see broadband advertised in Tbps, or terabits per second, on the market any time soon. And broadband measured in Kbps is rare these days too, since most connections are now much faster.

Comparing broadband packages

Finding a good deal for broadband is easy if you compare broadband quotes on MoneySuperMarket, where you can find deals that offer your ideal connection speed at the best possible price. All you need to do is enter your postcode for an accurate list of deals and providers in your area, and you’ll be given a list of deals close to you.

Then you can compare them by their monthly cost as well as any set up costs involved, the average speed you’ll get, any limits on downloads, and whether or not they include additional offers like vouchers. You can save deals you like the look of, and once you’re ready to pick you’ll be on your way to better broadband.

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