Low storage is the most common reason iOS updates fail, backups stall, and apps start crashing. The fix is almost always the same short list of actions, and none of them require deleting things you care about. This guide walks through them in order of impact, using the storage tools Apple builds into iOS and iPadOS.
Step 1: See What Is Actually Using Space
- Open Settings > General > iPhone Storage (or iPad Storage)
- Wait a few seconds for the color-coded bar to finish loading: it shows how much space Photos, Apps, Media, Messages, and System Data occupy
- Scroll down: every app is listed by size, largest first
- Read the recommendations iOS shows below the bar, such as “Offload Unused Apps” or “Review Large Attachments”
That screen is your map. Work the largest categories first instead of guessing.
Step 2: Apply the iOS Recommendations
iOS generates personalized suggestions on the same screen. The common ones:
- Offload Unused Apps: removes apps you rarely open while keeping their documents and data. The home screen icon stays with a small cloud badge; tapping it reinstalls the app with everything intact
- Review Large Attachments: shows message attachments sorted by size so you can delete the videos and photos clogging your conversations
- Review Personal Videos / Downloaded Videos: lists large videos so you can delete ones you no longer need
Tap Enable for the automatic ones, or tap a recommendation to review what it wants to remove.
Step 3: Understand Offload vs. Delete
The difference matters:
| Offload App | Delete App | |
|---|---|---|
| App itself | Removed | Removed |
| Documents and data | Kept on device | Deleted |
| Reinstall behavior | Everything returns as you left it | Fresh install, sign in again |
| Best for | Apps you use occasionally | Apps you are done with |
Enable automatic offloading so iOS does this for you when space runs low:
- iOS 26 and later: Settings > Apps > App Store > Offload Unused Apps
- Earlier iOS versions: Settings > App Store > Offload Unused Apps
You can also offload a single app manually: tap it in iPhone Storage, then tap Offload App.
Step 4: Clear the Usual Space Hogs
Photos and videos (usually the biggest category)
- Enable iCloud Photos with Optimize iPhone Storage (Settings > Photos): full-resolution originals move to iCloud and lightweight versions stay on the device. Note that this needs iCloud space, and the free 5 GB tier rarely covers a real photo library
- Empty the Recently Deleted album (Photos > Albums > Recently Deleted): deleted photos sit there for 30 days still counting against your storage. Select and delete them permanently
Messages
- Set messages to auto-delete: Settings > Apps > Messages > Keep Messages (choose 30 Days or 1 Year)
- Delete large attachments via the “Review Large Attachments” recommendation from Step 2
Downloaded media
- Streaming apps (Netflix, YouTube, Spotify, Podcasts) hold gigabytes of downloads you may have already consumed. Clear them inside each app’s downloads section
Safari
- Settings > Apps > Safari > Clear History and Website Data: clears cached files and cookies. This also signs you out of most websites, so expect to log in again
App caches
- Apps like social media accumulate caches they don’t let you clear directly. The practical fix: delete the app and reinstall it. The cache goes with the delete; your account stays intact
Step 5: What NOT to Bother With
- Third-party “cleaner” apps: iOS sandboxing prevents them from clearing system caches. They mostly repackage what Settings already offers, sometimes with a subscription attached
- Manually deleting “System Data”: that category includes caches and files iOS manages itself. The system clears them automatically when space runs low
- Deleting iCloud content from the storage screen: items stored in iCloud don’t occupy device space in the first place
Also know that “Storage Almost Full” alerts often clear on their own: iOS evicts cached and temporary files when it needs room. Restart the device and give it a few minutes before concluding the numbers are stuck.
Step 6: If You Need Space for an iOS Update
Major iOS releases typically want around 10 GB free on the device, and the download plus unpack process needs temporary room on top of that:
- Work through Steps 2-4 above; offloading a few large apps alone usually frees several gigabytes
- Still short? Update via a computer instead: connect to Finder, iTunes, or the Apple Devices app and update from there. The computer handles the download, so the device needs far less free space. See our IPSW installation guide for the manual route
- After a successful update, check iPhone Storage for the old update file: tap it and select Delete Update to reclaim the space
Full update preparation is covered in our guide to avoiding iOS update problems.
Keep It Clear Automatically
Three settings prevent the problem from returning:
- Offload Unused Apps enabled (Step 3)
- iCloud Photos with Optimize Storage if your photo library is the main occupant
- Messages auto-delete set to 1 year or 30 days
Set those once and the “Storage Almost Full” alert becomes rare. And whenever you are about to update or restore, pair the freed space with a current backup from our backup guide.