1. See what is using the space
Start with the free overview built into iOS:
- Open Settings.
- Tap General, then iPhone Storage.
The bar at the top shows what is used by apps, photos, messages, the system and so on, and the list below shows each app's share. Apple's page explains that cached and temporary data might not count as usage, and that iOS removes cached and temporary files by itself when it needs space — there is nothing for you or any app to clear there.
2. Try Apple's recommendations
The same screen can show recommendations for your iPhone. Tap Show All if it is there, read each one, then tap Enable to turn it on or tap the recommendation to review what you could delete. Apple also lists the usual large items: photos and videos, Messages attachments, videos downloaded in streaming apps, files in the Files app, and apps you no longer use. You can have iOS remove unused apps automatically while keeping their data (Settings → Apps → App Store → Offload Unused Apps).
3. If Photos is the big one
For most people the photo library is the largest single item. Free options first:
- Duplicates. Photos finds duplicate photos and videos by itself: in the Photos app go to Collections → Utilities → Duplicates and merge them. See how to delete duplicate photos.
- iCloud Photos with Optimize iPhone Storage. If you pay for enough iCloud storage, this keeps the full-resolution originals in iCloud and smaller versions on the iPhone. It is on by default when iCloud Photos is on; Apple's page shows where the setting lives.
- Videos. A video usually takes far more space than a photo. Photos can show videos on their own (Collections → Media Types → Videos), so you can look at the long ones first.
4. Then empty Recently Deleted
This is the step people miss. Anything you delete in Photos stays in Recently Deleted for 30 days, and it keeps using space until it leaves. If you have just deleted a lot and the number in iPhone Storage hasn't moved, that is almost always why — see why storage didn't go down and how to empty Recently Deleted.
What no app can do
iOS doesn't let an app clear another app's cache, the “System Data” category or memory, and an app can't empty Recently Deleted either. Cleaning those up is iOS's job, and it does it by itself.
Doing it with Oxid Photos
Oxid Photos (not released yet) cleans the photo library and nothing else. It shows how full the iPhone is, then lets you go through the library in a few ways: swiping month by month, groups of duplicates and similar shots with the reason one was picked to keep, old screenshots, and videos longest first. Live Photos can be kept as just the still.
Nothing is deleted from a swipe or a group. Everything you mark goes to a Review Pile; you delete from there, and iOS asks you to confirm. Afterwards the app shows that space as pending in Recently Deleted rather than “freed”, because that is what it is, and tells you how to free it. It is free; Pro ($2.99 once) adds things like one-tap suggestions and batch tools. About Oxid Photos.
Sources
The iPhone steps on this page were checked on 13 October 2026 against Apple's own support pages. Menu names can move between iOS versions; if yours differs, Apple's page for your version is the one to follow.
- How to check the storage on your iPhone and iPad — Apple Support
- Manage storage on iPhone — Apple Support
- Merge duplicate photos and videos on iPhone — Apple Support
- Locate photos and videos by media type on iPhone — Apple Support
- Delete or hide photos and videos on iPhone — Apple Support
- Back up and sync your photos and videos with iCloud — Apple Support