Why your mobile data allowance matters more than the headline price
When you choose a phone plan, the monthly price gets all the attention. The number that quietly decides whether you are getting good value is your mobile data allowance, the pile of gigabytes you can use each month before you hit a cap or pay extra.
Here is the catch. Networks love to advertise enormous allowances, 100GB, 150GB, sometimes unlimited, because a big number feels like a bargain. Most of us never get close to using it. Pay for a mobile data allowance you do not need and you are handing over money every month for headroom that just sits there.
This guide covers how much data a typical person really gets through, how to check your own usage in a couple of minutes, and how to move to a plan that actually fits, without losing your number.
How much mobile data do you actually need?
For most people, a fair bit less than they think. Ofcom figures suggest the average UK user gets through only around 5GB to 6GB of mobile data a month, yet plans with 100GB or more are everywhere you look. Ofcom’s latest figures show total UK mobile use is still climbing, up roughly 18% in a year, but that growth is driven by heavy streamers rather than the average household.
The reason the gap is so wide is simple. Most of the data-hungry stuff, box sets, big downloads, hours of video, happens on wifi at home or at work. On mobile data you are mostly browsing, messaging, checking maps, music and social media. As a rough guide:
- Light use, mainly messaging, maps and the odd video: often under 5GB a month.
- Average use, daily social media and some music streaming: roughly 5GB to 15GB.
- Heavy use, lots of video on the move or tethering a laptop: 30GB or more, where a large or unlimited mobile data allowance genuinely earns its keep.
If you are a heavy user, a big allowance is the right call and nobody should talk you out of it. The point is to match the plan to your habits rather than to a marketing number on a poster.
Why a bigger data allowance is not always better value
Most of us buy “just in case” headroom. We picture the one month we might stream a whole box set on the train, so we pay for 100GB and then use a tenth of it. Every month. Forever. That unused gap is money for the network and nothing for you.
Unlimited can be worth it if you genuinely run through huge amounts, or if your phone is your main internet connection at home. For an average phone, though, an unlimited mobile data allowance is usually insurance you never claim on. If you have drifted onto a giant plan out of habit, you could well be paying more than you need to, depending on your usage.
How do you check how much data you really use?
Open your network’s app or your online account, where every provider shows your monthly data use. It takes a couple of minutes and it is the single most useful thing you can do before switching.
Look back over the last three months rather than one, since a holiday or a house move can throw a single month out. Take your highest month, add a little breathing room, and that is your real number. Used 8GB, 6GB and 11GB over those months? A 20GB plan covers you comfortably and a 100GB one is money down the drain. Match your mobile data allowance to that real number and you stop paying for thin air. It is also worth knowing the difference between SIM-only and a handset deal, which our guide on SIM-only or phone contracts breaks down in full.
Big networks, smaller brands and where the cheaper deals hide
The UK has four networks that own the actual masts: EE, O2, Three and Vodafone. Almost every other brand you see, names like Smarty, Voxi, Giffgaff, iD Mobile, Lebara and 1pMobile, is a virtual operator, or MVNO, that rents space on one of those four networks.
That matters because it means a smaller brand can run on the same masts and the same coverage as a big network, often at a lower price. The smaller players tend to spend less on advertising and high-street shops, and some of that saving lands in their tariffs. A right-sized mobile data allowance on one of these lower-cost networks is often where the real saving sits, depending on the deal and your usage. If you are switching anyway, it is a good moment to see whether an eSIM suits you, as many networks now activate one in minutes.
How to switch network and keep your number
Switching is quicker than most people expect, and you keep your number. Text the word PAC to 65075 and your current provider has to text back your switching code, usually within a minute. That code, your PAC, stays valid for 30 days.
Hand the PAC to your new network when you sign up and they do the rest. Under Ofcom’s rules the switch completes within one working day, and the regulator has banned providers from charging you for a notice period that runs on after your switch date. If you are already out of contract there is nothing to pay to leave, so check that first. Heading abroad soon? It is worth a look at how to avoid roaming charges before you travel.
Before you switch, run this quick check
- Look up your real data use over the last three months.
- Add a little headroom, then ignore the giant allowances above it.
- Check coverage for the network you are eyeing in the places you actually go.
- Confirm you are out of contract, or check any early-exit fee.
- Text PAC to 65075 when you are ready, to keep your number.
Once you know your real number, comparing like-for-like plans takes minutes and the right-sized one is usually a good deal cheaper than the giant allowance you are on now.
Frequently asked questions about mobile data allowances
- What happens if I go over my mobile data allowance?
- It depends on the plan. Some networks simply charge for extra data, some slow your speed once you hit the cap, and others let you cap usage so you can never be billed for more. Check the wording before you pick, especially if you choose a smaller allowance.
- Is unlimited data worth it?
- Only if you genuinely use a lot, for example streaming video on the move every day or using your phone as your main home connection. For an average user who is mostly on wifi at home, a smaller mobile data allowance usually costs less for the same experience.
- Will switching network affect my coverage?
- Coverage depends on which of the four mast networks your brand uses, not on the brand’s size. A smaller, cheaper provider running on the same network gives you the same signal, so it is worth checking which network a deal runs on for your area.
- How long does it take to switch and keep my number?
- Once you give your new network your PAC code, the switch is set to complete within one working day under Ofcom’s rules. There is usually a short window where your old SIM stops working and the new one takes over with your number.
