What Is App Size?
Table of Content:
App size is the amount of storage an app takes to download, install, and run on a user’s device. Simple answer to what is app size: it is the weight of your app package, plus the files the store or device needs to deliver it properly. On the store page, users usually see a download size. On the device, they may see a larger installed size because the app gets unpacked, optimized, and starts storing data.
Tiny detail. Big business consequence.
A 40 MB app and a 400 MB app may look similar in screenshots. The user does not feel them the same way when mobile data is weak, storage is low, or they need the app right now.
App size meaning
App size sounds like a technical metric, but app teams should treat it as a conversion and retention signal.
For developers, it affects build structure, assets, dependencies, device support, install success, and update delivery.
For app marketers, it can affect store page conversion because users can see app size before downloading.
For app CEOs and publishers, it belongs in the growth conversation because every extra megabyte can create friction, especially in countries where users have older devices, smaller storage, expensive data, or unreliable Wi-Fi.
So no, app size is not just “how many MB the build has.”
It is part of the install experience.
Why app size matters
Google Play says app size can affect both install and uninstall metrics, and recommends keeping the app as small and optimized as possible even when apps are technically under the platform limits. Google Play Console also shows app download size, size compared with peers, size over time, active devices with under 2 GB of free storage, and uninstall ratio on those low-storage devices.
The conversion argument is even sharper.
In a Google Play analysis, smaller APK sizes correlated with higher install conversion. For apps under 100 MB, every additional 6 MB correlated with a 1% drop in install conversion rate. Google also found that an app around 10 MBhad a download completion rate about 30% higher than an app around 100 MB.
Market context makes the story less theoretical. The same Google Play analysis found that in emerging markets, around 70% of people considered app size before installing because of data cost and storage concerns. A 10 MB reduction correlated with about a 2.5% install conversion increase in markets like India and Brazil.
Google’s example: if an app gets 10,000 installs per month in India at a 20% conversion rate, reducing the APK by 10 MB could mean roughly 1,140 extra installs per month.
That data is older, yes. Still useful as directional evidence. The user psychology has not disappeared: storage warnings, mobile data anxiety, slow networks, and “I need this app now” moments still change install behavior.
How app size works
App size changes depending on where you measure it.
Before release, the team sees build size in Xcode, Android Studio, App Store Connect, or Play Console. After upload, Apple and Google may process, compress, split, thin, or optimize the package. Then the store displays a download size to users. After installation, the device may show a different storage number because the app is unpacked and starts generating user data, cache, media, databases, logs, or downloaded content.
That is why teams get confused.
A developer says, “The build is 120 MB.”
A marketer says, “The store shows 78 MB.”
A user says, “It takes 310 MB on my phone.”
Everyone may be right. They are just looking at different versions of app size.
App size vs download size vs install size
Term | What it means | Where teams usually see it | Why it matters |
App size | General term for how large the app is across build, download, or device storage contexts | Store listing, developer tools, analytics reports | Helps teams discuss app weight as a product and growth issue |
Download size | The compressed size users download from the app store | App Store, Google Play, Play Console, App Store Connect | Affects install friction, mobile data concerns, and download completion |
Install size | Space the app takes after installation | Device storage settings, platform tools | Affects low-storage users, uninstall risk, and device experience |
App data and cache | Files created after the app is used, like saved media, preferences, logs, offline files, and cache | Device storage settings, app diagnostics | Can make a “small” app feel heavy over time |
Update size | Size of the new app version or patch users need to download | Store updates, release tools | Affects update completion and whether users stay on old versions |
The clean takeaway: optimize the size users feel, not just the size your build system reports.
App size limits on Apple App Store and Google Play
Apple and Google both have size limits, but those limits should not become your target. A store may accept a huge app. Users may not.
For iOS and iPadOS apps with a minimum deployment target of iOS 9 or later, Apple lists a 4 GB maximum uncompressed app size and an 80 MB maximum executable file size. Apple also notes that Background Assets can host larger assets separately from the build for iOS, iPadOS, macOS, tvOS, and visionOS apps.
Google Play size limits are based on compressed download size.
- The base module limit is 500 MB, individual feature modules are 500 MB,
- individual asset packs are 1.5 GB,
- install-time modules and asset packs can total 4 GB,
- on-demand or fast-follow asset packs can total 30 GB,
- and the total maximum compressed download size for apps published on Google Play is 34 GB.
Google also says apps over 200 MB show users on mobile data a non-blocking dialog that warns them about the large size.
For Android apps, Android App Bundles help reduce user download size because Google Play generates optimized APKs for each device configuration. In plain English, users download only the code and resources their device needs, not every asset for every screen density, language, CPU, or feature.
Example of app size in ASO
Imagine a travel app competing in Southeast Asia.
The listing looks strong. Nice icon. Good screenshots. Clear promise: cheap flights and hotel deals. Keyword rankings are improving. Product page views are up.
But installs are not moving.
Then the team checks app size. The Android download is heavy because the app ships every language pack, high-resolution image assets, unused libraries, and several features most new users do not touch on day one.
That is not only an engineering cleanup task.
It is an ASO problem because people can abandon before install. It is a product problem because the first session starts with waiting. It is a business problem because paid traffic gets more expensive when conversion leaks at the download step.
A smarter release moves non-essential assets after install, trims unused code, uses optimized image formats, and ships a lighter first-download experience. The app still has the same features. The user just does not have to carry the whole suitcase through the front door.
How app teams should track app size
Track app size release by release, not once a quarter when someone complains.
The useful view looks like this:
- Download size by platform and country
- Installed size by device class
- Size compared with category peers
- Size change by release version
- Install conversion before and after major size changes
- Uninstalls among users with low free storage
- Update completion rate after large releases
- Asset, SDK, and dependency contribution to total size
Google Play Console already gives Android teams size-related reporting, including app download size over time and peer comparison. That makes it easier to catch size creep before it quietly becomes conversion damage.
For ASO teams, pair that with store conversion, keyword visibility, ratings, and review themes. If users mention “too big,” “takes forever,” “won’t install,” “no storage,” or “update failed,” app size has moved from technical debt into customer feedback.
How to reduce app size
Start with the boring stuff. It usually works.
Remove unused code. Compress images. Audit SDKs. Split features. Avoid shipping assets users do not need on first launch. Use platform delivery systems instead of packing everything into the base app.
For Android, App Bundles can generate optimized downloads for each device, and Play Feature Delivery lets teams move certain features into modules that download later or only when needed. Google also recommends shrinking the app by removing unused code and resources.
For iOS, check assets, binaries, frameworks, debug symbols, duplicate resources, video files, and heavy onboarding media. Apple also points developers to app thinning and Background Assets when larger assets should be managed separately from the main build.
A good rule: your first install should include what the user needs to experience value. Not every future feature, every media file, every market asset, and every nice-to-have library your team forgot to remove.
Related terms
FAQs
What is app size in simple words?
App size is how much space an app takes to download, install, and run on a device. The size shown in the app store is usually the download size. The size shown in device storage can be larger because the app gets installed, unpacked, and starts storing data or cache.
Why does app size matter for ASO?
App size matters for ASO because it can affect install conversion. Users may hesitate to download a large app when storage is low, mobile data is expensive, or the connection is slow. Google Play has also said app size can affect install and uninstall metrics.
Is app size a ranking factor?
App stores do not present app size as a simple public ranking factor. Still, app size can influence behavior around the listing: install completion, conversion rate, low-storage uninstalls, and user reviews. Those outcomes matter for app growth, even when the size itself is not treated like a direct keyword ranking signal.
What is a good app size?
A good app size is as small as possible without hurting the first user experience. There is no universal number because a banking app, photo editor, game, and navigation app have different asset needs. The better benchmark is your category peers, your target markets, and conversion performance by release.
What is the difference between app size and app data?
App size usually refers to the app package or installed application. App data is what the app stores after use, such as saved files, cache, settings, offline content, downloaded media, or account data. A lightweight app can still become heavy if it stores too much data over time.
