What are bits and bytes?

Terms like ‘bits’ and ‘bytes’ are used extensively nowadays, from mobile data plans to broadband line speeds. However, these two related but distinct terms need explaining, especially since they’re used to measure different things.

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Bits and bytes

What are bits and bytes used for?

The simple answer is almost everything that happens in the digital world. You use kilobytes and megabytes of data for all online activities, including:

  • Email

  • Instant messaging

  • Video calls

  • Social media

  • Web browsing

  • Online apps

  • Streaming

  • OS updates.

Computers, tablets and smartphones measure their storage in bytes, so you’ll know how much free space you have for programs and files. Overloading computers and mobile devices can cause them to run slowly.

Your broadband and mobile connection speeds are measured in bits, and these figures will help you to differentiate between superfast and ultrafast broadband.

Are bits and bytes the same thing?

The simple answer is no, though they are related. To explain the relationship between them, it’s necessary to momentarily delve into computer terminology.

A bit is the smallest unit of data in existence. It comprises either a zero or a one, since computers can only understand binary data. Believe it or not, everything digital devices do is programmed using endless strings of zeroes and ones. It takes billions of individual bits to stream a Netflix show, or play FIFA on your PS5.

For practicality, bits are accommodated in blocks of eight known as bytes. Bytes are used to measure size, whereas individual bits are used to measure speed. As the larger unit, the former is referred to with an uppercase B, whereas bits are referenced with a lowercase b. They’re usually also prefixed with a larger volume, since one bit and one byte contain insignificant volumes of data.

If a 20MB (MegaBytes) file is being downloaded at 20Mbps (Megabits per second), it’ll take eight seconds to download, because a byte is eight times larger than a bit. Of course, you don’t actually need to conduct these mathematical equations. The only thing you need to keep an eye on is your data allowance, to ensure you have enough bytes left to cover downloads and browsing.

What’s the difference between a megabit and a megabyte?

The same rules apply for megabits and megabytes – one measures speed, the other measures size. The changing prefixes simply tell you how many bits or bytes you’re working with:

  • 1,024 bytes/bits = Kilo

  • 1,024 kilobytes/kilobits = Mega

  • 1,024 megabytes/megabits = Giga

  • 1,024 gigabytes/gigabits = Tera.

The reason we’re quoting 1,024 rather than 1,000 is because of the binary system used by computers, which means bits and bytes are measured in powers of two. Two to the power two is four, two to the power three is eight, then 16, 32 and so forth – right up to 1,024, or 210.

Documents will often be measured in KB, while most other media will occupy several MB. Large files like standalone software programs will be measured in GB, whereas TB is usually reserved for measuring the capacity of hard drive or cloud storage. 

How can I tell bits and bytes apart?

Bits and bytes use the same letters in their abbreviations, which can be confusing, but the formatting distinguishes them. As explained above, a byte is written with an uppercase B, so, a 1,000-byte file would be labelled as 1KB, or one kilobyte. A bit is written with a lowercase b, so, 1,000 bits of data being transferred per second would be labelled as 1Kb. 

How do I calculate gigabit to megabyte, and so on?

You don’t need any mathematical acumen to understand bits and bytes – your current and historic broadband or phone plans will have served you well enough without unpicking the science behind the numbers. Search engines can help with calculations, but the main things to remember are the difference between bits and bytes, and the scale outlined two paragraphs earlier.

If your home broadband connection has an average download speed of 60Mbps, and you wish to download a 60MB file, you’ll need to wait eight minutes. Of course, most files sizes aren’t going to be perfect multiples of your download speeds, so this maths can soon become unwieldy – and largely unnecessary. 

How many bits should my broadband connection have?

There’s no set number of bits required for a satisfactory broadband connection, but a basic ADSL internet connection will require speeds of at least 9Mbps to qualify as such. The more bits your line can handle at any given second, the faster your broadband will be. 

Fibre broadband options include superfast and ultrafast connections. Their typical speeds are summarised below:

Updated 19 June 2020

Most UK households can get by with superfast speeds, even when one person is streaming while another plays a computer game online. Ultrafast will support more devices and enable access to content in HD or 4K quality. Hyperfast is still something of a work in progress, with a handful of providers like Hyperoptic offering it in select areas. 

Can my internet get more bits?

You can try to upgrade your broadband plan to achieve faster speeds, but keep in mind some things will affect your performance regardless of your chosen internet service provider or package:

  • Your distance from the telephone exchange

  • The quality of the network cables in your area

  • The presence of fibre optic cables in your area

  • The presence of ultrafast/hyperfast providers in your area.

Do I need to know about bits and bytes?

A detailed technical understanding is largely irrelevant for consumers, but it’s worth familiarising yourself with what these terms mean. For example, knowing about bytes can help you understand available phone storage, download capacity or even email attachments. Understanding bytes can give you a better understanding of the broadband plans you’re signing up for. 

It can also help you manage your data allowance better if you know an Ultra HD movie comes in at 18GB while the same movie at 1080p (more than sufficient for viewing on a mobile device) is just 2GB. That’s a huge data saving, and only the largest TV screens or projectors would demonstrate a significant improvement in picture quality using a 4K source file.

Last updated: 25 November 2020