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100GB of data - How much is it and how long does it last?

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Last updated: 22 August 2022

When searching for mobile phone deals and SIM only contracts, it’s important to consider how much data you need per month. Getting too little means you might be cut off or have to pay for costly add-ons, while getting too much means you’ll end up paying unnecessarily for a service you don’t use.

A lot of network providers in the UK offer 100GB monthly data plans. But how much is that? And how long does it last? We’ve put together this short guide to help you decide whether it’s enough for you. 

What is 100GB?

100GB stands for 100 gigabits of data. 1 gigabit of data is equivalent to 1,000 megabits, so 100GB amounts to a pretty healthy 100,000 megabits. Gigabits shouldn’t be confused with gigabytes, which are often used in measuring download speeds. For more info, check out our guide on the difference between a bit and a byte.

How much is 100GB of mobile data?

Many network providers offer 100GB SIM-only deals, including all of the Big Four plus a range of MVNOs. Prices start at just £12 per month from providers like Three and iD Mobile, while you could be paying as much as £30 per month if you opt for O2 or BT Mobile. Therefore, it’s important to compare mobile plans before committing, as the savings you can make on a 12 or 24-month contract are potentially huge.

Compare these deals that offer 100GB per month:

Pay as you go 100GB deals

Currently just one network provider offers 100GB of data on a PAYG SIM, and that's O2, throwing in unlimited calls and texts for a total of £30. See deal.

1 month 100GB deals

A number of smaller network providers offer 100GB of mobile data on rolling monthly SIM contracts, including TalkMobile, iD Mobile, and Asda Mobile:

Provider Calls and texts Monthly cost
TalkMobile Unlimited £12 See deal
iD Mobile Unlimited £14 See deal
Asda Mobile Unlimited £25 See deal

12 month 100GB deals

Quite a few network providers offer 100GB of mobile data per month on 12-month contracts, including most of the Big Four. Take a look at the some of the following deals:

Provider Calls and texts Monthly cost
iD Mobile Unlimited £12 See deal
Three Mobile Unlimited £12 See deal
Vodafone Unlimited £20 See deal
O2 Unlimited £20 See deal
BT Mobile Unlimited £30 See deal

24 month 100GB deals

Three network providers currently offer 100GB monthly data plans on 24-month SIM only contracts - Three, BT Mobile, and iD Mobile:

Provider Calls and texts Monthly cost
iD Mobile Unlimited £14 See deal
Three Mobile Unlimited £16 See deal
BT Mobile Unlimited £25 See deal

How long does 100GB last?

With 100GB of mobile data, you can browse the internet for more than 69 days straight, stream music for almost a month, and watch up to 13 days plus of Netflix. This is a fair chunk, and with 100GB of data per month you could be browsing the internet or social media constantly, watch Netflix for up to 11 hours per day, and download almost 100 iOS apps per day (based on the average app size on the AppStore).

This is what you can do with 100GB of data:

Browsing the internet 69 days 11 hours 24/7
Browsing social media 46 days 7 hours 24/7
Sending files via email 10,000 files on average 333 files per day
Streaming music 27 days 19 hours 22 hours per day
Watching YouTube (480p) 15 days 19 hours 12 hours per day
Watching YouTube (720p HD) 4 days 19 hours 4 hours per day
Watching YouTube (1080p Full HD) 2 days 13 hours 2 hours per day
Watching Netflix (Low quality) 13 days 21 hours 11 hours per day
Watching Netflix (SD) 5 days 23 hours <5 hours per day
Watching Netflix (HD) 1 day 9 hours 1 hour per day
Watching Netflix (UHD) 14 hours 17 minutes 28 minutes per day
Video calling (SD) 7 days 17 hours 6 hours per day
Video calling (UHD) 2 days 14 hours 2 hours per day
Downloading/updating apps (Android) 8,696 apps on average 289 apps per day
Downloading/updating apps (iOS) 2,907 apps on average 96 apps per day

Is 100GB of data enough for me?

Based on the above table, 100GB of data per month should be more than enough for most mobile users. In fact, according to Ofcom’s latest Communications Market Report, the average mobile user consumed 4.5GB of data per month in 2020, so 100GB is far, far higher than your average allowance.

That being said, if you love listening to music all day on Spotify, or you watch Netflix on the commute to work every day, then 100GB per month should be a fair amount to keep you going.

The only time you’d really need more than this, however, is if you like to stream content in HD or Ultra-HD. For example, with 100GB per month you could watch around 30 minutes of Netflix per day in Ultra-HD. However, even if you only want to watch one half-hour show each day, this will leave no room for doing anything else online, including simply browsing the internet or social media.

So, heavy data consumers should consider higher allowance than 100GB, or even go unlimited, while medium users should be satisfied. If you’re a light user, and you only use your phone to send the odd email or browse Twitter occasionally, you could save a lot each month by opting for a much smaller data allowance, such as 1GB, 5GB, or 10GB per month.


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Fergus Cole

Author: Fergus Cole

Fergus is a journalist specialising in the personal finance, energy and broadband sectors. He also has a passion for travel and adventure so tries to make the most of this in any spare time he gets.

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