Mobile data: how much do you need?

Remember when free texts and minutes were the main factors in choosing a phone contract? These days we barely even notice them, but we face a more modern dilemma when contemplating signing on the dotted line: how much mobile data is enough? It’s difficult to know the exact answer; like the free minutes that used to be wasted every month, many of us pay over the odds for data we don’t need.

Every case is different. A user with Wi-Fi at home and in the office will consume much less than a user for whom their mobile phone is the office. However, even a short commute can easily become the main data drain if you want entertaining – in October, a Citrix Bytemobile report found that video streaming accounts for 50% of the world’s mobile traffic.

It’s an eye-opening figure, so to back it up with data of our own, we posted a request on Twitter for anyone who would be willing to be our guinea pig. We asked them to install a data-monitoring app on their smartphone, and track their real-world 3G and Wi-Fi usage for seven days. By coincidence, exactly 100 people volunteered to take part in full; a further 50 estimated figures were submitted but not included in the data analysis, although we did trawl them for interesting insights.

This feature tackles the big question with a two-pronged approach. First, we choose the apps that you say commonly drink up your data allowances, and see how hungry they really are. Then we analyse the survey figures to find out how much monthly data the average user needs. The results may surprise you.

Mobile data: the media hogs

One of the questions participants were asked was which apps they used most during the test period, and it’s safe to say the same culprits cropped up repeatedly for those people with high data consumption: BBC iPlayer, Spotify and YouTube. As expected, media-streaming apps run up the big numbers.

To determine just how big, we ran a series of mobile phone tests using both the office Wi-Fi connection – which conveniently clocks in at 12Mbits/sec, the average EE says we can expect over 4G – and a 3G connection on the 3 network that we’ve measured achieving anything from 200Kbits/sec up to 1Mbit/sec.

Testing with both means that we can ascertain the data consumption of each app in its various quality settings – including those the 3G connection couldn’t handle without throttling.

An hour of Spotify radio streaming would use anything from 53MB to just over 212MB depending on connection and playback quality

First up is Spotify. The mobile app offers Normal, High and Extreme quality settings, which equate to Ogg Vorbis streams at approximately 96Kbits/sec, 160Kbits/sec and 320Kbits/sec – so you can already estimate the bare minimum amount of data they’ll use over time. We measured ten minutes of Spotify streaming at each quality setting, then repeated the tests and averaged the results to make up for any variation in tracks. The difference between Wi-Fi and 3G consumption was negligible, and we couldn’t discern any audible difference between the two through our Sennheiser headphones.

Those ten minutes of Soft Cell and Rick Astley classics consumed an average of 8.9MB at Normal quality, 21.3MB at High quality and 34.7MB at Extreme quality. Taking the lowest and highest of the figures we recorded, an hour of Spotify radio streaming would use anything from 53MB to just over 212MB depending on connection and playback quality. That’s worth bearing in mind the next time you set off for work relying on a Toto album to prepare you for the day ahead.

However, it’s nothing compared with the damage done by streaming video. To test BBC iPlayer, we used an hour-long special of The Thick of It, which is listed as 637MB when downloaded at High quality over Wi-Fi. That’s fine for download – the file size is labelled clearly enough that you know exactly what you’re getting – but what about when streaming the same episode?

Over 3G on an iPhone 5, with the picture sharp except for a few momentary lapses into pixellation, ten minutes of viewing consumed 32.6MB, so for the full hour you’d be looking at just short of 200MB. On Wi-Fi, with no connection speed constraints on picture quality, the same ten minutes consumed 75.5MB, for an hourly total of around 450MB. For many people, that would be a month’s data allowance gobbled up by a single TV episode.

Finally, there’s YouTube. We have a ready-made test in the form of the 9mins 57secs Big Buck Bunny 1080p animation we use to test playback on netbooks. The quality over 3G wasn’t perfect, with constant artefacts and a lack of sharpness; the near-ten-minute clip consumed 18.9MB. Over Wi-Fi, the picture was crisp and flawless, making full use of the iPhone 5’s 1,136 x 640 display, and the same clip consumed 161MB. Stretch that over an hour and you’re looking at almost 1GB.

Of course, data requirements for video and audio streaming are only ever as high as your connection allows – if your videos are obviously coming across at low quality, you have less to worry about when it comes to data caps – but with EE promising an average 4G speed around 12Mbits/sec, these adaptive bit rates will have a greater effect. If you’re planning to move to 4G, it’s unwise to assume your data use will stay as it is; in many cases, the same applications will use more data automatically.

Maps was one service that a few people listed as a likely culprit for their high use, and if we take Google’s version as an example, they may be right. While planning a route from our GPS-detected location, with full satellite imagery enabled and some judicious scrolling and zooming involved, our phone sucked down 31MB in a few minutes. If you’re on the move and worried about your cap, stick to the basic line map.

What about less intensive uses, such as social networking and web browsing? These aren’t as bad for data, but they can still consume more than you might think. Loading five stories on the PC Pro website used 3.4MB. Opening a large Facebook photo album, allowing the thumbnails to populate, then opening five of them to full-screen consumed 6.1MB. Checking emails used a tiny amount, and you can always check the size of an attachment or set your client to not download images. Our advice if you’re suspicious of a particular app is to download a traffic monitor for yourself to see how much it’s using.

Measuring our readers

You can get an idea of the kind of allowance you need by looking at how many of those data-intensive apps you use, and how often – but don’t assume everyone uses a phone in the same way. For every high roller who mainlines Sky Go and Spotify Premium, there’s another who barely checks emails when out for the day.

Consumption averages are skewed upwards by a relatively small number of heavy users, and they use a lot of data

According to EE, the average monthly data consumption for an Orange customer with a 1GB data cap is only 380MB. The average for T-Mobile’s uncapped “Full Monty” package is a much higher 1.5GB, but 70% of those users don’t actually break the 1GB barrier. Our survey figures back up these findings – averages are skewed upwards by a relatively small number of heavy users, and they use a lot of data.

First, here’s a quick statistical breakdown of our willing 100: we had 74 Android users, 23 were on iOS, and three had BlackBerry or Windows Phone handsets. We converted the weekly figures to monthly so that they match the data caps available on phone contracts.

The consumption figures ran the full gamut. At the bottom end, a surprising 25 people would use less than 100MB in the month, with 14 of them using less than 30MB and five not even hitting 10MB. To show the lengths to which some people go to keep data use down, one used 3G mainly for email, but “waited until on Wi-Fi to download attachments”.

The number of people using very small amounts of data shows just how skewed any average will inevitably be by the heavier data users. From the graph shown above, you can see that 46 of the 100 users would be perfectly fine with a 250MB monthly limit, and 57 with a 500MB limit. The 1GB limit would be enough for 78 of the 100 users surveyed, and only nine users could legitimately claim to need an “unlimited” contract. Of course, which data caps are available will depend on your network.

When networks talk of “fair use” policies applying to their unlimited tariffs, they’re referring to those few users that gobble up vast amounts of data. Two users consumed 2.3GB and 2.9GB in a single week – in both cases, the phone was the main internet connection for the house, with one saying he was “very pleased at how well the telephone coped”. We had to filter out two further examples that claimed consumption of more than 25GB each in a week – even if they’re accurate, they make the average consumption of our 100 participants a massive 3.7GB a month.

The frugal users far outnumber the heavyweights, but the latter drag everything upwards

Without those two outliers, the average is more feasible, but still high, at 933.6MB a month. However, to show how little relevance the average figure has for the majority of users, the median of the 100 results is a much more modest 279.5MB a month. The frugal users far outnumber the heavyweights, but the latter drag everything upwards.

Although we didn’t include the other 50 submissions in the key data analysis, since they weren’t accurately tracked, we were surprised by how low their estimates were compared to the reality of the 100.

Across 27 Android users, 14 on iOS, and nine divided between BlackBerry, Symbian and Windows Phone, the average estimate was 223MB a month and the median was 100MB. It’s too small a group from which to draw firm conclusions, but could it be that people use more data than they think they do?

The power of Wi-Fi

A common point made by our survey participants was that the availability of Wi-Fi has increased recently, whether that’s due to rollouts on public transport or the growing popularity of hotspot bundles with home broadband contracts. Plus, the majority of those questioned said they’re connected to Wi-Fi at all times when at home, and a large number when at work too.

The average across the 91 people who used Wi-Fi was around 2.8GB of data a month, showing just how much of the slack is taken up by our home and work internet connections.

The median was 1.4GB so, unlike the results of our 3G study, the heaviest users aren’t unduly skewing the average.

The simple fact is that sufficient access to Wi-Fi can make the difference between needing 1GB of mobile data a month and 100MB, and over the course of a two-year contract, that can add up to quite a saving. Of course, contract prices for mobiles and for broadband vary widely, but don’t simply assume that paying a little more for an unlimited phone contract and using it as your home internet connection will work out cheaper.

We consume more data when we’re on Wi-Fi because we can, because data caps are much more generous or non-existent. It’s notable that several people said they had “all-you-can-eat” 3G data from the 3 network, and for that reason, they used a smartphone as the main home internet connection. People will use whatever is the cheapest or most convenient option.

How much mobile data do you need?

We can give you average figures and median figures, and the kind of figures that we didn’t think would be possible on a 3G connection, but the only one that matters is your own. There are simple ways to find out how much data you use, whether via Android’s built-in meter, any of the numerous third-party traffic-monitoring apps, or even by simply going online and looking at a breakdown of your bills. The networks aren’t compelled to inform you if they notice you paying for data you don’t use every month, so be proactive and find out.

The networks aren’t compelled to inform you if they notice you paying for data you don’t use every month, so be proactive and find out

Once you have a rough idea of how much data you need, look at the apps you use regularly. That Netflix account makes the daily commute more bearable, but it also swallows chunks of your data allowance – most people will conclude that the money spent is worth it for the entertainment value, but you may notice apps that aren’t worth the cost. It also pays to set your phone to download app updates, podcasts and Newsstand items over Wi-Fi only.

The future looks interesting, not least because 4G speeds threaten to make our current 3G data consumption look miniscule. As we all get used to Full HD on the move, you can also expect video to make up much more than its current 50% of mobile traffic. Take an interest in your data consumption, and be sure to choose a tariff that gives you the headroom to use a phone as it should be used.