This new phone setting could quietly cut your data use in half on UK networks – but hardly anyone has turned it on

From doom‑scrolling on the train to streaming in bed, mobile data now fills the gaps between almost everything else we do. That convenience has a price: creeping bills, mid‑month “you’ve used 80% of your allowance” texts, and a quiet dread of autoplay video when you’re nowhere near Wi‑Fi.

Most people react the same way. They blame one app, cut back a bit, maybe nudge their plan up a tier and carry on. What almost nobody does is open the one setting that phone makers built precisely for this problem - a single switch that tells your handset to behave as if every megabyte costs money.

Buried a few screens deep, “Low data” or “Data saver” modes can trim mobile data use by anything from a quarter to well over half. Yet on UK networks, usage stats suggest only a small minority have them turned on.

It is not magic. It is a bundle of very ordinary changes - fewer background refreshes, smaller images, lazier auto‑play - applied ruthlessly across your apps. The result feels surprisingly normal, especially once you’ve lived with it for a few days. For anyone on a capped plan, it can be the difference between coasting to the end of the month and eyeing the meter in fear.

The hidden “low data” switch most people never touch

Both major mobile platforms now ship with a system‑wide data‑saving mode:

• On iPhones and iPads: Low Data Mode
• On Android phones: Data Saver (sometimes also called Data saving or Lite mode by manufacturers)

If you bought or upgraded a phone in the last few years, your device almost certainly has one of these options. They are not turned on by default, partly because networks still like selling bigger bundles, and partly because Apple and Google do not want to change how your favourite apps behave without asking.

Instead, the feature sits there quietly in Settings, waiting for the kind of person who actually reads their tariff small print. Most of us never reach that far. We scroll past it hunting for Wi‑Fi passwords or Bluetooth, then go back to wondering where all the gigabytes went.

Think of it as telling your phone: “Pretend I’m roaming abroad all the time. Be stingy unless I’m on Wi‑Fi.”

Once enabled for mobile data, it sends a clear signal to apps and the operating system: do the same job using less.

What actually changes when you flip it

Under the bonnet, low‑data modes pull several small levers at once. No single one sounds dramatic, but together they add up.

Typical changes include:

• Background data throttled or paused
  Social feeds, podcasts, email and cloud storage sync less often when you are on 4G or 5G, and catch up quickly on Wi‑Fi.

• Lower‑resolution media by default
  Apps are encouraged to stream video at standard definition rather than HD, fetch smaller images, and avoid downloading super‑high‑quality audio unless you ask.

• Fewer automatic downloads
  App updates, big attachments and cloud backups wait for Wi‑Fi. Some messaging apps delay downloading large videos in group chats until you tap them.

• Tracking and ads less chatty in the background
  The same rules apply to analytics and advertising SDKs. Less background chatter between phone and ad servers means fewer invisible megabytes leaking away.

• Tighter rules app by app
  On Android, you can whitelist a few essentials (for example, WhatsApp or Maps) to bypass the restriction. On iOS, some apps expose their own “Use less data” switches that only appear when Low Data Mode is on.

Put simply: the phone stops trying to give you the “best possible quality” by default and aims for “good enough unless told otherwise”.

In daily life, that usually means social apps feel the same, photos take a fraction of a second longer to sharpen, and auto‑playing clips look a bit softer when you are on the bus. The main thing you notice is your network’s “usage warning” texts arriving later or not at all.

Why this matters more on UK networks right now

Britain’s mobile offers look generous on billboards: “unlimited” here, 100 GB there, 5G symbols everywhere. The reality for many households is closer to:

• A bundle of 5–25 GB on a SIM‑only or budget contract
• Shared data across several family SIMs
• Patchy 5G, with 4G cells still doing most of the work in busy areas

That combination makes it very easy to drift over a cap without doing anything dramatic. A few HD Reels, an hour of tethering a laptop, some automatic app updates away from home - suddenly the text from your provider lands and you are either paying overage or toggling data off until payday.

Network engineers in the UK routinely see huge spikes from social video, cloud backup and app updates the moment people step outside their home Wi‑Fi.

Low‑data modes attack exactly those three categories. They will not help if you routinely stream 4K football over 5G for hours, but they are brutally effective against the quiet, always‑on trickle that most plans bleed from.

There is a network benefit too. During busy periods in city centres, limiting how “greedy” each handset is can help ease congestion. That is one reason some providers now nudge customers towards these settings in their help pages, even if they rarely shout about them in adverts.

How to turn it on in under a minute

The hardest bit is knowing where to look. After that, it is two or three taps.

On iPhone (Low Data Mode)

1. Open Settings → Mobile Data (or Mobile Service).
2. Tap Mobile Data Options.
3. Tap Data Mode.
4. Choose Low Data Mode.

You can also set it separately for Wi‑Fi:

1. Go to Settings → Wi‑Fi.
2. Tap the ⓘ next to your home network.
3. Toggle Low Data Mode on if you have a very limited broadband plan or are using a hotspot.

On Android (Data Saver)

The exact labels vary slightly between Samsung, Google Pixel and other brands, but the path is similar:

1. Open Settings → Network & internet or Connections.
2. Tap Data Saver or Data usage.
3. Toggle Data Saver on.

On most Android phones you can then:

1. Tap Unrestricted data or Allowed apps.
2. Pick a handful of apps (for example, messaging, maps, banking) that are allowed full access in the background even when Data Saver is on.

Let’s be honest: you will only do this once. It is worth taking the extra 30 seconds to tweak the list so that critical services behave exactly as you need.

How much data - and money - you might actually save

The impact depends heavily on how you use your phone, but usage logs from real‑world tests tell a consistent story: people who spend a lot of time in social feeds, messaging groups and maps see the biggest wins.

A rough pattern looks like this:

Typical usage pattern	Data saver OFF	Data saver ON
Light use (browsing, email, maps)	3–6 GB / month	2–4 GB / month
Social‑heavy (Reels, TikTok, WhatsApp)	10–20 GB / month	5–12 GB / month
Mixed use, some streaming	20–40 GB / month	12–25 GB / month

Those ranges are broad on purpose. What matters is the direction of travel: a cut of 20–50% is entirely realistic for many UK users, especially if you combine the system switch with a few tweaks inside big‑hitter apps (for example, setting Netflix to “Medium” quality on mobile and disabling autoplay in Instagram or X).

In pounds and pence, even dropping a single plan tier - from, say, 30 GB to 10–15 GB - can save several pounds a month on SIM‑only deals. For families running multiple SIMs, the compound effect across a year can quietly match the cost of a streaming subscription or two.

When you might not want it on

There are good reasons not to live in permanent data lockdown, and the setting is not all‑or‑nothing.

You might leave it off if:

• You genuinely have a cheap, truly unlimited 5G plan and are happy with your bill.
• You regularly use your phone as a hotspot for work, especially for video calls that need stable quality.
• You rely on certain apps (for example, cloud storage or camera backup) to sync immediately over mobile, not “when the phone feels like it”.

You might turn it on only sometimes if:

• You are travelling, especially on roaming caps.
• It is the second half of the month and your allowance looks tight.
• You are in a rural area with weak signal and want to squeeze more out of a flaky 3G/4G connection.

The good news is that both iOS and Android let you keep full quality on Wi‑Fi. You can be ruthless on mobile and relaxed at home.

Small extra tweaks that multiply the effect

Once you have flipped the main switch, a handful of in‑app changes can stack with it for even bigger savings without making your phone feel “crippled”.

Focus first on:

• Social and video apps
  Turn off auto‑play where you can, set “Use less data on mobile” if offered, and cap mobile streaming quality at SD or “Data saver”.

• Cloud backup and photos
  On Google Photos, iCloud or OneDrive, choose “Wi‑Fi only” backup for videos and full‑resolution media.

• Podcasts and music
  Download playlists and podcast episodes on Wi‑Fi before long journeys; lower the streaming quality for mobile data.

• Maps and navigation
  Download offline areas for regions you travel through often. This helps in patchy‑signal spots and keeps map data use low.

None of this requires turning your smartphone into a dumb phone. It is closer to telling each app: behave sensibly when I am paying per gigabyte.

The quiet psychology of leaving it on

There is a subtler benefit that does not show up on your bill. With a hard ceiling on background data, your phone becomes less “chatty” in general. Notifications still arrive, but the constant stream of invisible syncing and pre‑loading slows.

For some people, that creates a calmer feel to the phone - fewer nudges to check every little update the second it happens. For others, it is just comforting to know that if you hand your teenager a SIM with a small bundle, the phone itself will do some of the policing for you, instead of relying on willpower alone.

Good data habits are like good energy habits at home: a few small, boring changes that silently prevent nasty surprises later.

If you later move to a more generous plan or finally snag a fairly priced unlimited deal, you can simply turn the setting off and watch video at full quality again. Until then, it sits in your pocket, chipping away at waste each day with no drama.

FAQ:

• Will Data Saver or Low Data Mode make my phone slower?
  Not in the sense of processor speed. Pages may take a touch longer to fully load high‑res images or HD video on mobile data, but general app responsiveness stays the same.
• Can I still watch HD or 4K video with it on?
  Yes. You can usually override the automatic quality inside each streaming app for a given video. The system setting just pushes apps towards lower defaults.
• Will it break WhatsApp, banking or navigation apps?
  No, core functions continue to work. On Android you can whitelist critical apps so they ignore Data Saver in the background; on iOS most major apps respect Low Data Mode sensibly.
• Does it save battery as well as data?
  Often, yes. Fewer background transfers mean less radio time and a small but real reduction in power use, particularly on older phones.
• Is this the same as turning mobile data off entirely?
  No. You still have full access to the internet; the phone just behaves more frugally. Think of it as “diet mode”, not “airplane mode”.