| Most common data type collected | Location data (Widely reported across app store privacy labels) |
| Free apps vs. paid apps | Free apps are more likely to rely on data collection for revenue |
| Background data collection | Many apps collect data even when you're not actively using them |
| User control tools | Both iOS and Android allow per-app permission review and revocation |
| Privacy labels available on | Apple App Store and Google Play Store (Introduced by Apple in 2020, Google in 2022) |
| Data deletion rights | Available to some users under laws like CCPA (California) (Verify applicability based on your state) |
The Data Apps Quietly Collect
When you download a free app, data is often the real currency. Apps collect information to personalize your experience, serve ads, improve their product — and sometimes share or sell that data to third parties. Understanding what's being gathered is the first step toward making smarter choices about which apps you trust.
| Most common data type collected | Location data (Widely reported across app store privacy labels) |
| Free apps vs. paid apps | Free apps are more likely to rely on data collection for revenue |
| Background data collection | Many apps collect data even when you're not actively using them |
| User control tools | Both iOS and Android allow per-app permission review and revocation |
| Privacy labels available on | Apple App Store and Google Play Store (Introduced by Apple in 2020, Google in 2022) |
| Data deletion rights | Available to some users under laws like CCPA (California) (Verify applicability based on your state) |
Here's a plain-English breakdown of the most common data categories and what they actually mean for you. For a deeper look at the specific permissions that enable this collection, see why apps ask for so many permissions.
A Glossary of Common Data Types
Apps rarely explain in plain terms what they're collecting. The glossary below defines the most frequently gathered data types so you can recognize them when you read a privacy policy or permission prompt.
Location Data
Information about where you physically are, derived from GPS, Wi-Fi networks, or cell towers. Apps can collect this continuously in the background, not just when you're actively using them.
Device Identifiers
Unique codes assigned to your phone, such as an advertising ID or IMEI number. These allow apps and ad networks to recognize your device across different apps and sessions, even without you logging in.
Behavioral Data
A record of how you interact with an app — which screens you visit, how long you spend on each, what you tap, and in what order. This is used to infer interests and habits.
Contact List Access
Permission to read the names and phone numbers stored in your phone's address book. Apps often request this to enable features like finding friends, but it also gives them data about people who never agreed to share their information.
Inferred Data
Conclusions an app draws about you based on other collected data — for example, inferring your income level from your location history and shopping patterns, even if you never provided that information directly.
Metadata
Data about your data. For example, a photo's metadata can include the time it was taken and the GPS coordinates of the location, even if the image itself doesn't reveal that.
Third-Party SDKs
Software toolkits built by outside companies (such as analytics or ad firms) that developers embed in their apps. These SDKs may collect data independently, sending it to the third-party company, not just the app developer.
Data Broker
A company that buys, aggregates, and resells personal data collected from many sources, including apps. You may never interact with a data broker directly, but they may hold detailed profiles about you.
Most of these data types don't exist in isolation — apps often combine them. Your location history paired with your purchase behavior, for example, creates a much more detailed profile than either piece alone. This combination is sometimes called data aggregation, and it's a key reason why individual permissions that seem harmless can add up to significant privacy exposure.
If you're curious about how websites use similar tactics, cookies and tracking tools work in closely related ways.
Why Apps Want This Information
79%
of apps share data with third parties
According to research published by Pew Research Center on American attitudes toward privacy and app data sharing.
45+
Average number of apps on a US smartphone
Based on general industry estimates; the exact figure varies by device and user habits.
~60%
of apps request location access
Location is among the most frequently requested permissions across both iOS and Android platforms.
Data collection typically serves one or more of three purposes:
- Product improvement: Crash reports and usage patterns help developers fix bugs and refine features.
- Personalization: Your activity history and preferences let apps tailor content, recommendations, and settings to you.
- Advertising: Behavioral and demographic data is used — directly by the app or sold to ad networks — to target you with relevant ads. This is often the primary revenue model for free apps.
None of these purposes are inherently wrong, but they vary greatly in how much data they actually require. A weather app needs your location to show local forecasts; it does not need access to your contacts or microphone. When an app's data requests go beyond what its core function demands, that's worth questioning.
Not All Data Collection Is Equal
Some data collection genuinely improves your experience — a mapping app needs your location to give directions. The concern arises when collection goes beyond what a feature requires, or when data is shared with parties you'd never expect. Reviewing permissions periodically, rather than once at install, gives you ongoing control as apps update their practices.
For practical habits that reduce your data footprint without disrupting daily app use, see our guide on keeping personal information safer while using everyday apps.
How to Check What an App Knows About You
Both Android and iOS give you tools to review and limit app data access without deleting the app entirely:
- Check app permissions: Go to your phone's Settings, find the app, and review which permissions — location, camera, contacts, microphone — are currently granted. Revoke any that seem unnecessary.
- Review privacy labels: The Apple App Store and Google Play both display privacy nutrition labels showing what data an app collects and whether it's linked to your identity.
- Read the privacy policy: These are long, but searching for keywords like "sell," "share," or "third party" quickly surfaces the most important clauses. For help decoding the language, reading the fine print in app agreements is a useful companion.
- Use data deletion rights: Under laws like the California Consumer Privacy Act (CCPA), some users have the right to request that a company delete their data. Many apps now include a "Delete my data" option within settings.
Social apps deserve particular attention — social media profiles can reveal far more than intended, even before you factor in what the app collects in the background.