When choosing a phone contract, a very important factor is the amount of data available. You definitely don’t want too little, as it could mean you’ll run out long before your monthly allowance renews, but too much will mean you pay for more than you need for the duration of your contract.

Here’s our guide on how to work out the amount of data you really need.

What uses up the most mobile data?

  • HD video: 3-5GB per hour
  • 4K video: around 7GB per hour
  • Music streaming: 120MB per hour
  • Web browsing: 1-4MB per minute
  • Facebook: 1-2MB per minute
  • Skype / FaceTime / Video chat: 100MB to 1.5GB per hour (depending on video quality)

The smallest amount of data you'll get per month is 500MB. This isn't really enough, and you'll probably struggle to make 1GB stretch a whole month if you use your phone a lot on your commute, for example. 2GB is a reasonable amount, and virtually everyone will use less than 6GB per month. Only the biggest YouTube or Netflix bingers will need more than 12GB.

Don't forget, you can usually download videos and watch them offline, and there's no point in watching 4K content on mobile devices: most don't have 4K screens so that extra detail is simply wasted.

Wi-Fi or 4G?

A common point of confusion is the difference between mobile data and Wi-Fi. While both give you access to the internet, they are different sources. Mobile data is provided solely by your mobile provider (BT, EE, O2, Three, Vodaphone, etc.) and is part of your contract.

When you're connected to Wi-Fi, the data used does not come from your mobile data allocation. Your home broadband connection will be your main source of Wi-Fi access, but you can often connect to Wi-Fi in public places such as hotels, coffee shops, or some restaurants. As an aside, it's well worth using a VPN when you do connect to public Wi-Fi.

So, the thing to work out before signing on the dotted line (or clicking on a deal as we do these days), is how much access you’ll have to Wi-Fi. Does your workplace allow personal devices to connect to Wi-Fi? Do you intend to watch YouTube or Netflix while away from home? Can you download stuff before you leave the house or office to then watch offline? 

Determining the necessity of accessing mobile data will give you a better indication of how much your plan should contain.

How much data do things like video and music use?

One of the greediest mediums for data is video streaming. Netflix states that an hour of standard definition content will use around 1GB of data, while HD content can gobble up a portly 3GB or 7GB if you want 4K UHD. This should be the same across similar streaming sites like NowTV, Amazon Prime Video, BBC iPlayer, and others.

You can set the Netflix app to default to lower quality when on data, but unless you’re happy with blurry images you’ll still be ploughing through your data plan at a hefty pace. There is a plentiful supply of content you can watch offline, so if you want to keep your data usage to a sensible amount here's how to download Netflix.

Music is less of an all-consuming black hole, but if you’re someone who wants to stream everything then it will bite into your data limit after a while. If you’re using Apple Music, Google Play Music, Spotify, or one of the other popular music subscription services then there’s a good change that your content is set at the higher 256Kb/sec rate which provides great quality without going overboard. 

how much data do i need

This roughly equates to around 120MB for each hour of streamed content. At this rate, you’d go through 1GB of data every eight hours or so. To put this into monthly terms, listening to an hour a day would amount to just over 3.6GB.

It’s important to know that most music and video streaming services adapt their quality to the speed of your connection. This is why a YouTube or iPlayer video can revert to a blocky mess when you have a weak connection, then upgrade to a sharper, higher-quality picture and soundtrack when the connection is better.

The reason you need to bear this in mind is if you’re in a city centre with a strong 4G connection, then you might end up watching the HD version of a video and using up much more data than when you’re served the lowest-quality version.

How much does browsing and social media take up?

Webpages don’t match the large file sizes of video streaming services, but there has been an increase in the number of videos that are now shown on news and review sites. EE estimates that web browsing now equates to between 1-4MB per minute, depending on how visual the site may be.

This means that an hour of browsing lighter sites will cost 60MB, while busier ones could be as much as 240MB. Facebook is stated to have a rate of about 1-2MB per minute, while you’ll need to also factor in uploading any images, which come in at around 1.5MB per image.

Basically, the more images and videos, the higher the dent in your data plan.

How much data does Skype, FaceTime or other video calling use?

Due to the high data usage caused by video, making calls to people on Skype, FaceTime, and other video chat apps can quickly use up quite a lot of data. Much depends on the quality of your camera and connection, so if you have a many megapixel set of optics sending out your visuals in glorious HD, then expect your data plan to suffer.

Once again, we defer to EE that estimates anywhere between 100MB and 1.5GB per hour for calls, depending on the resolution of the video.

How much data does Email use?

As email is largely text, albeit with and increasing amount of graphics through emoji, GIFs, and other accoutrements, it doesn’t use up much data at all, meaning you can correspond with friends to your heart’s desire without wreaking havoc on your monthly allowance.

Use the calculator

We’ve outlined the various ways that data can be used over the course of a month, and hopefully this gives you a clue as to how much your plan should contain. If you’re still unsure though, it’s probably a good idea to check one of the data-use calculators offered by mobile providers. We know of ones from Vodaphone, Three, and Giff-Gaff, which means you can try them all, work out the average, and go from there.

how much data do I need

For a guide to the pick of the current mobile plan crop, check out our Best SIM only deals and Best phone deals guides.