DB Labs
Quick Answer
The iPhone "Other" category (called "System Data" in iOS 15+) is filled by Safari cache, streaming app offline caches, iOS system files, Siri models, and iCloud Drive local copies. Normal size is 5-15 GB. To shrink it: clear Safari cache (Settings → Safari → Clear History and Website Data), restart your iPhone, and offload streaming apps. If still above 25 GB, a backup-and-restore via Finder is the most effective solution, bringing System Data down to 5-8 GB.
What Is 'Other' Storage on iPhone?
Apple renamed the "Other" category to "System Data" in iOS 15, but the underlying contents are the same. When you look at the storage breakdown bar in Settings → General → iPhone Storage, you see categories like Photos, Apps, and Media — everything that does not fit neatly into those categories lands in System Data/Other.
Apple intentionally keeps the contents of this category vague. There is no line-by-line breakdown. This makes it frustrating to manage. For a detailed explanation of each component, see our dedicated article on what iPhone System Data contains.
What Fills the Other Category?
| What Fills Other/System Data | Typical Range | Clearable? |
|---|---|---|
| Safari cache, cookies, offline reading list | 1-10 GB | Yes |
| Spotify, Netflix, Apple Music caches | 2-20 GB | Yes — offload app |
| iOS system caches and logs | 1-5 GB | Partly — restart |
| Siri voice models and language data | 1-3 GB | No |
| iCloud Drive local copies | 1-15 GB | Yes |
| iOS update remnants | 0-5 GB | Yes — restore |
| iMessage attachment cache | 0.5-5 GB | Partly |
| Fonts and system assets | 0.5-2 GB | No |
What Size Is Normal vs. Bloated?
- Under 10 GB: Excellent — well maintained
- 10-15 GB: Normal for everyday use
- 15-25 GB: Above average, cleanup is worthwhile
- 25-40 GB: Bloated — aggressive cleanup or restore recommended
- Over 40 GB: Very unusual — almost certainly a restore is needed
Step-by-Step Reduction Plan
1 Clear Safari Cache (Biggest Impact)
Go to Settings → Safari → Clear History and Website Data. Confirm by tapping Clear History and Data. This removes all Safari browsing data, cookies, and cached content. You will be logged out of websites and need to re-enter passwords. Recover: 1-10 GB. This is the single highest-return action for most users.
2 Restart Your iPhone
Hold side + volume down, slide to power off, wait 30 seconds, restart. iOS flushes temporary system caches during a power cycle. Recover: 1-3 GB typically. Always do this after clearing Safari cache — the combination often reduces Other by 5-10 GB total.
3 Offload Streaming Apps
Go to Settings → General → iPhone Storage, find Spotify, Apple Music, Netflix, YouTube, or Podcasts and tap Offload App. Streaming apps cache enormous amounts of data that shows up in Other/System Data rather than under the app's own storage entry. Heavy Spotify users (with downloaded playlists) can recover 5-15 GB from this step alone.
4 Reduce iMessage History
Go to Settings → Messages → Keep Messages and change from Forever to 1 Year. iOS will prompt to delete older messages and their photo/video attachments. iMessage attachment caches can reach several gigabytes for users who exchange many photos in conversations.
5 Disable iCloud Drive Offline
Go to Settings → [Your Name] → iCloud → iCloud Drive. If you have Desktop & Documents syncing enabled, consider disabling it or removing large files. Also turn off offline access for individual apps that you do not need available without internet.
When to Restore Your iPhone
If your Other/System Data remains above 25 GB after completing all the steps above, a backup-and-restore is the most thorough solution. A clean iOS install removes all accumulated caches, orphaned update files, and fragmented data that cannot be cleared through settings alone.
Steps:
- Back up to iCloud: Settings → [Your Name] → iCloud → iCloud Backup → Back Up Now
- Connect to Mac, open Finder, select iPhone, click Restore iPhone
- After setup completes, restore your backup
- System Data should now be 5-8 GB
Preventing Future Growth
To keep Other/System Data under control going forward:
- Restart your iPhone once a week to flush temporary caches
- Clear Safari cache monthly, or whenever it exceeds 1-2 GB
- Avoid letting streaming apps download too much offline content
- Keep at least 10% of your total storage free as working space
- Consider an annual backup-and-restore as part of your storage hygiene routine
For a comprehensive approach to managing all iPhone storage categories, see our complete iPhone storage guide. If your storage keeps filling up even after clearing Other, check our article on why iPhone storage keeps filling up.
While You're Cleaning Up Storage
After shrinking System Data, photos are often the next biggest category. Swype Photo Cleaner makes it fast to delete duplicates, blurry shots, and screenshots — swipe left to delete, right to keep.
Free · iPhone · iOS 16+ · 100% on-device, zero uploads
Free · iPhone · iOS 16+