How to Save Data on iPhone: 8 Settings That Cut Cellular Use

Updated November 3, 2026

The fastest way to save data on iPhone is to find out which apps are using it, turn on Low Data Mode, and stop your phone from quietly using cellular when Wi-Fi is weak. After that, keep big jobs like backups, app updates and video for Wi-Fi.

Here's how to do each one, with the exact settings, plus what ads and trackers on web pages have to do with your data bill.

First, check what's using your data

Before changing anything, see where your data is going:

Open Settings → Cellular (called Mobile Data or Mobile Service in some regions).
Scroll to the list of apps and tap Show All. The amount each app used appears under its name.
Tap System Services to see what iOS itself used, such as iCloud and software updates.

One thing trips a lot of people up: the Current Period number counts from the last time you tapped Reset Statistics at the bottom of that screen, not from the start of your billing cycle. If you've never reset it, it can cover months. Reset it on the day your plan renews to get a useful number. For the most accurate total, check with your carrier.

Turn on Low Data Mode

Low Data Mode is the biggest single switch. It stops apps from using the network in the background, turns off Background App Refresh, lowers streaming quality, and pauses automatic downloads, backups and iCloud Photos updates. Apps you're actively using still work.

On LTE/4G: Settings → Cellular → Cellular Data Options, then turn on Low Data Mode.
On 5G: Settings → Cellular → Cellular Data Options → Data Mode, then choose Low Data Mode.
With Dual SIM: Settings → Cellular, tap the number you use for data, then turn on Low Data Mode.

You can also turn it on for a single Wi-Fi network, which helps with a phone hotspot or a metered connection: go to Settings → Wi-Fi, tap the info button next to the network, then turn on Low Data Mode. Apple explains what changes in each app in Use Low Data Mode on your iPhone and iPad.

Turn off Wi-Fi Assist

If your iPhone uses lots of data even though you're "always on Wi-Fi", this is the usual reason. Wi-Fi Assist is on by default and switches to cellular when your Wi-Fi connection is poor, so a weak home or office network can quietly cost you data.

On iOS 26 and earlier: go to Settings → Cellular, scroll to the bottom, and turn off Wi-Fi Assist. The amount it used is shown just below the switch.
On the newest iOS: Apple replaced it with Connectivity Assist, which now lives in Settings → Wi-Fi. Scroll down and turn it off. You can also turn it off for just one network.

The trade-off is that pages may load slowly on bad Wi-Fi instead of switching to cellular. See About Connectivity Assist for details.

Turn off cellular data for apps that don't need it

Back in Settings → Cellular, every app in the list has its own switch. Turning one off means that app only uses Wi-Fi. Good candidates:

Streaming video and music apps you only use at home
Games, which often download extra content and play video ads
Photo and file apps that sync large files, including iCloud Drive
Apps you rarely open but that still show data use

Leave on the apps you need away from Wi-Fi, like Maps, Messages and your banking app. Apple's guide Use cellular data on your iPhone or iPad covers these switches in more detail.

Limit Background App Refresh to Wi-Fi

Background App Refresh lets apps fetch new content while you're not using them. It's handy, but it adds up on cellular.

Open Settings → General → Background App Refresh.
Tap Background App Refresh at the top and choose Wi-Fi (or Off).
Below that, turn it off for individual apps that don't need fresh content.

Keep updates, backups and photos on Wi-Fi

Large automatic transfers are easy to miss because they happen on their own:

App Store: go to Settings → Apps → App Store and turn off Cellular Data, or adjust its automatic download options, so app updates wait for Wi-Fi.
iCloud Photos and iCloud Drive: turn off cellular data for Photos and iCloud Drive in the Settings → Cellular list. Low Data Mode also pauses iCloud Photos updates and automatic backups.
Podcasts and Music: download episodes and playlists at home rather than streaming them on the go.

Save videos on Wi-Fi and watch them offline

Video uses far more data than reading, messaging or browsing, so it's where planning ahead pays off most. If you know you'll watch something on the bus or a flight, download it on Wi-Fi first. Then it plays from your phone's storage and uses no data at all.

Many streaming apps have their own download button. For videos on web pages, Kipzy shows a Save video button when a page has a video: pick the quality (the file size is shown first) and tap Download. To make sure this never touches your plan, turn on Settings → Download on Wi-Fi only in Kipzy. Downloads keep going in the background and pick up where they left off. Protected videos and live streams can't be saved, and you should only save videos you have the right to keep. Our guide on saving videos to watch offline covers the other options too.

Block ads and trackers while you browse

Ads aren't free to download. On many web pages, the banners, auto-playing video ads, tracking scripts and pop-ups are extra files your phone has to fetch on top of the article you came for. On cellular, all of that comes out of your plan, and it also makes pages slower.

Safari can't block ads by itself, but you can add a content blocker from the App Store and turn it on in Settings → Apps → Safari → Extensions. Another option is a browser with blocking built in. Kipzy blocks ads, trackers and pop-ups before they load, using the EasyList and EasyPrivacy filter lists, which update automatically. Its Privacy Report shows what was blocked on each site, so you can see what you didn't download. If a site breaks, tap the shield in the address bar to turn blocking off for just that site. Ad blocking is free and works in every Kipzy tab, though it doesn't affect other apps. Read more about blocking ads on iPhone or see how the Kipzy ad blocker works.

Common questions

Why is my iPhone using so much data?

The usual causes are video streaming, Wi-Fi Assist switching to cellular on weak Wi-Fi, iCloud Photos or backups syncing, apps refreshing in the background, and automatic app updates. Check Settings → Cellular to see which one it is before turning everything off.

Why does my iPhone use cellular data when I'm on Wi-Fi?

Almost always Wi-Fi Assist (or Connectivity Assist on the newest iOS). When your Wi-Fi is slow or not connected to the internet, it uses cellular to keep things loading. Turn it off as shown above.

Should I leave Low Data Mode on all the time?

If you have a small plan, yes, it's safe to leave on. The trade-offs are lower streaming quality, no background refresh, and iCloud Photos and backups waiting until you're on Wi-Fi. If you notice an app isn't updating, open it and it will refresh.

Why doesn't my iPhone's number match my carrier's?

Your iPhone counts since the last reset, while your carrier counts by billing cycle and may measure differently. Reset the statistics on your renewal date, and use your carrier's app or account page as the final word.