Gigabit vs gigabyte: What's the difference?

A gigabit (written as Gb, with a lowercase b) is a way of measuring speed. When it comes to broadband, it tells you how quickly data can travel from the internet to your home and onto your devices.

One gigabit is equal to one billion bits per second, which gives you an idea of just how much information can move at once. You’ll usually see gigabits mentioned when broadband speeds are being talked about, such as:

• 100Mbps

• 500Mbps

• 1Gbps (often referred to as gigabit broadband)

In simple terms, the higher the number, the faster your connection. That means less time waiting for pages to load, quicker downloads, and smoother streaming, even when lots of devices are online at the same time.

A gigabyte (written as GB, with a capital B) is a way of measuring size, not speed. Instead of telling you how fast something happens, it tells you how much data there is or how much storage something takes up.

One gigabyte equals one billion bytes, and it’s a unit you’ll come across all the time when browsing - from film and TV downloads to apps, games, and the storage space on your device or in the cloud.

To put that into context:

• A HD film is usually around 3–5GB

• A large video game can be 50GB or more

• Many smartphones come with 128GB of storage or higher

While gigabits are all about how fast data moves, gigabytes are about how much data there is to move in the first place, or how much storage space a file is going to take up.

Gigabit vs Gigabyte: What’s the difference?

The simplest way to tell a gigabit and a gigabyte apart is to focus on what each one measures. A gigabit (Gb) is all about speed, while a gigabyte (GB) is about size – how much data there is, rather than how fast it moves.

That tiny capital letter really does matter. A lowercase b stands for bits, which are used to measure broadband speed and data transfer rates. A capital B stands for bytes, which are used to measure file sizes and storage space.

It’s a small detail, but it makes a big difference, and it’s the main reason gigabits and gigabytes are so easy to mix up.

Your broadband speed, measured in gigabits, determines how quickly you can download or upload data. The file size, measured in gigabytes, tells you how much data there is to move in the first place.

Put simply, bigger files with lots of gigabytes will take longer to download, while faster broadband speeds – like Gigabit broadband - can dramatically reduce the waiting time.

For example, if a film is 10GB in size, the downloading experience can be very different depending on your connection and broadband speed. On slower broadband, that download could take a long time. On faster broadband packages, like our Gigabit broadband, the very same film could be ready to watch in just minutes.

Understanding the difference between a gigabit and a gigabyte can make comparing broadband packages a lot simpler. It helps you focus on what really affects your day-to-day experience, rather than just the numbers on the page.

If your household streams lots of TV and films, games online, works from home, or has lots of devices connected at the same time, faster speeds can make the world of difference. Broadband options with higher speeds are better equipped to handle all that activity at once, keeping things running smoothly no matter what you are up to.

In the end, it’s not about how much data you download or how many files you are working with – it’s about how quickly your broadband can keep up with everything you’re doing.

Once you know the difference between gigabits and gigabytes, it’s easier to see why speed matters. If your home is juggling streaming, gaming, and video calls across multiple devices at once, faster broadband can help everything run more smoothly.

Take a look at your current broadband speed and see whether it’s keeping up with how you use the internet, or whether it is time to make the switch to a faster speed. If you’re thinking about upgrading your package, explore our broadband deals to see what broadband speeds you can get.