What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Open Settings, tap Cellular (called Mobile Data or Mobile Service on some iPhones), then scroll to the app list. The amount beneath each app is its cellular-data use for the statistics period shown on the phone. Compare those figures to find the largest users, and switch off an app’s cellular-data control if it should use Wi-Fi only.
Find the iPhone’s per-app mobile-data list
Apple’s built-in view is the most direct way to see which individual apps have used cellular data. It does not require a separate monitoring app or a carrier login. The exact wording can vary by iOS version, region, carrier and SIM configuration, so look for the equivalent of Cellular, Mobile Data or Mobile Service.
As an Amazon Associate I earn from qualifying purchases.
- Open Settings.
- Tap Cellular. If that label is not present, tap Mobile Data or Mobile Service.
- Scroll down to the list of apps.
- If the list is abbreviated and a Show All control appears, tap it to expand the app list.
- Compare the usage amount displayed beneath each app. The largest figures identify the apps that have consumed the most cellular data during the period represented by the phone’s statistics.
The list is an attribution view: it tells you how much cellular data iOS has associated with each app. It is not a combined cellular-and-Wi-Fi usage report. Activity performed over Wi-Fi is not added to the cellular figure shown for an app.
Crashes, No Sound, or Screen Glitches?
Random freezes, missing sound and display glitches usually trace back to one bad driver. Find and replace yours safely.Free scan · under a minutePC Slower Than It Used to Be?
A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11How to read the numbers correctly
The figures cover a statistics period
iPhone keeps a running set of cellular statistics until they are reset. The figures therefore describe the interval beginning at the last reset, not necessarily the current month, your contract month or the period used on your carrier bill. Before judging an app’s behavior, scroll to the bottom of the Cellular or Mobile Data screen and note when the statistics were last reset.
If the reset date is unknown or far earlier than your current plan period, treat the totals as historical context. You can reset them and begin a fresh observation window, but record the reset date so later comparisons have a clear starting point.
App data and Wi-Fi data are different measurements
An app can appear to be a light cellular user while transferring substantial data over Wi-Fi, because the built-in list counts cellular traffic only. Conversely, a high cellular figure means the app used that amount away from Wi-Fi during the tracked interval; it does not describe the app’s total network activity across all connections.
Dual SIM changes which line is measured
On a Dual SIM iPhone, the displayed usage is tied to the cellular-data number selected for data service. Check which line is selected before comparing totals. If you change the data number, interpret the figures in that context rather than assuming the list represents both lines as one undifferentiated total.
Identify the biggest users without misreading the screen
Compare the app amounts, rather than relying on position
Scroll through the expanded list and compare the amounts shown under the app names. Do not assume that the first visible app is the largest user; the useful result comes from comparing the displayed values across the list. If necessary, make a short note of the largest few figures before changing any settings.
Check System Services separately
Above or near the app entries, iPhone lists System Services as a separate category. Some cellular traffic is attributed to iOS services rather than to an individual app. This explains why the app list may not account for every byte that appears in a broader device or carrier total.
Apple does not provide an individual cellular-data switch for each System Services entry from that list. You can inspect the category to understand that system activity exists, but it is not managed in the same per-app way as the controls below it.
Use the carrier’s figure for billing questions
The iPhone list is useful for finding app-level contributors, while the carrier’s record is the authority for the most accurate current-period total. If a plan-limit warning, invoice or usage dispute is involved, compare the phone’s statistics with the carrier’s report and use the carrier’s measurement for billing decisions. Differences can result from different reset dates, data-number selection on a Dual SIM phone, system-service traffic or the carrier’s own accounting period.
Quick wins for a faster PC:
Scan for outdated or missing drivers - takes under a minuteDriver Scan →Clear out junk files and repair common Windows errorsFree Scan →Block cellular data for one high-use app
Once you have identified an app you do not want using mobile data, you can deny it cellular access from the same screen.
- Open Settings.
- Tap Cellular, Mobile Data or Mobile Service, depending on the label shown on your iPhone.
- Scroll to the app list and locate the app.
- Turn off the cellular-data control beside that app.
With the control off, the app uses Wi-Fi for data. The setting is targeted: it does not change cellular access for other apps. The practical trade-off is that the app may not receive, refresh or upload data while the iPhone is away from Wi-Fi. If that app is needed while travelling or outside a known Wi-Fi network, leave cellular access enabled or turn it back on when necessary.
| Choice | Scope | What happens away from Wi-Fi | Use it when |
|---|---|---|---|
| Turn off cellular data for one app | Only the selected app | That app uses Wi-Fi only for data | One app is responsible for an unwanted or disproportionate cellular total |
| Leave the app enabled | No restriction for that app | The app can continue using cellular data | The app must update or communicate when Wi-Fi is unavailable |
| Enable Low Data Mode | Broader cellular or Wi-Fi connection setting | Background network activity is restricted more generally | You want system-wide reduction rather than a single-app block |
Use Low Data Mode for broader reduction
Low Data Mode is a system-level option intended to restrict background network use and save network data. It is different from the per-app list: it helps reduce activity, but it does not tell you which app used the data and it does not replace the per-app controls.
The available path and wording depend on whether the connection is LTE/4G, 5G, Wi-Fi or a Dual SIM configuration, as well as on carrier setup. Open the relevant cellular or Wi-Fi settings and look for the Low Data Mode control associated with that connection. Enable it for the connection on which you want broader restrictions.
Choose Low Data Mode when several apps or background processes are contributing to usage and you want a general network-saving measure. Choose the individual app switch when you want a precise exception or want to keep other apps unrestricted. Because Low Data Mode changes background behavior more broadly, check the apps and services you depend on after enabling it.
Reset statistics to measure a new period
Resetting the on-device counters is useful when you want to observe usage from a known starting point—for example, after changing a plan, travelling or disabling a high-use app. It does not change your carrier’s records and does not automatically align the iPhone with your billing cycle.
- Open Settings.
- Tap Cellular, Mobile Data or Mobile Service.
- Scroll to the bottom of the page.
- Tap Reset Statistics and confirm the reset if iPhone asks.
- Record the reset date and, on a Dual SIM iPhone, the cellular-data number selected at that time.
After the reset, the app figures represent only activity since that moment. Keep the phone’s reset date consistent with the period you are trying to study; otherwise two readings taken at different starting points cannot be compared fairly.
A reliable workflow for finding and reducing usage
- Open the cellular settings. Use the label your iPhone shows: Cellular, Mobile Data or Mobile Service.
- Confirm the data line. On a Dual SIM phone, verify which number is selected for cellular data.
- Check the statistics date. Find out when the counters were last reset before interpreting the amounts.
- Expand the list. Tap Show All when it appears so every relevant app is visible.
- Compare app figures. Identify the largest cellular totals, remembering that Wi-Fi traffic is not included.
- Inspect System Services. Account for cellular activity that is not assigned to an individual app.
- Choose the narrowest useful control. Turn off cellular access for a specific app, or enable Low Data Mode when a broader restriction is appropriate.
- Reset only with a purpose. If you need a new measurement window, reset the counters and write down the date and data line.
- Use the carrier’s record for plan totals. Treat the carrier’s current-period figure as authoritative for billing or allowance disputes.
Troubleshoot surprising results
An app appears to use more data than expected
First verify that you are looking at cellular data rather than assuming the number includes Wi-Fi. Then check the statistics reset date. A counter that has been running for a long time can make a moderate recent change look large, while a recently reset counter can make a short burst look unusually prominent.
The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →The phone total does not match the carrier total
Compare the two measurement periods and confirm the selected cellular-data number if the iPhone has Dual SIM. Review System Services as well, because not all traffic is assigned to an app. For the most accurate current-period amount, rely on the carrier’s record.
You turned off an app’s cellular switch and it stopped updating
That is the expected consequence of the restriction when Wi-Fi is unavailable: the app has been limited to Wi-Fi data. Re-enable its cellular-data control if it needs to communicate or refresh away from Wi-Fi. If your goal is to reduce, rather than completely stop, background use across many apps, consider Low Data Mode instead.
You cannot find every app in the first view
Scroll farther down and use Show All if iPhone displays it. Menu labels and the exact arrangement can vary with iOS version, region, carrier and SIM setup, so look for the cellular-data settings area rather than an identical screen layout.
What this method can—and cannot—tell you
- It can show: each listed app’s cellular-data amount for the current on-device statistics period.
- It can help you do: compare app contributors, disable cellular access for a chosen app and start a new observation period by resetting statistics.
- It does not show: a combined cellular-plus-Wi-Fi total for an app.
- It does not automatically provide: the carrier’s billing-period total.
- It does not offer: an individual cellular-data shutoff for each System Services entry.
- It does not make Low Data Mode an attribution tool: Low Data Mode reduces background network use more broadly, but the per-app list is what identifies the largest app-level cellular users.
Best decision for most iPhone users
Start with the per-app list in Settings and compare the figures after checking the reset date and, where relevant, the selected Dual SIM data number. Disable cellular data only for apps that do not need to work away from Wi-Fi. If usage remains high across multiple sources, enable Low Data Mode for the affected connection. Keep the iPhone counters as an app-level diagnostic and use the carrier’s current-period report when the question is how much data remains on a plan or what amount should appear on a bill.
Recommended Free Tools
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
