iPhone 'Storage Almost Full' — How to Free Up Space

What it means

'iPhone Storage Almost Full — You can manage your storage in Settings' is a friendly warning, not an error — but it has real consequences.
When the iPhone is nearly full, app updates refuse to install, photos and videos won't save, iCloud Backup fails, and apps start to crash.
The easiest wins are clearing photos already backed up to iCloud, removing big apps with offline content (Spotify, Netflix), and emptying the Photos 'Recently Deleted' folder, which can free several gigabytes in a few minutes.

Affected Models

All iPhone models — most common on 64 GB and 128 GB devices
Same warning on iPad
Particularly noticeable after a year or two of heavy photo and video use

Common Causes

Photos and videos taking up the bulk of storage
Big apps with offline content (Spotify Downloaded, Netflix downloads, podcasts, games)
WhatsApp / Messages media accumulated over years
Recently Deleted in Photos still holding items for 30 days
Mail's offline attachment cache
Safari cache and reading-list offline pages
An old iOS update file that didn't get cleaned up

How to Fix It

See what's taking the space.

Settings > General > iPhone Storage.
Wait a minute for the bar at the top to fill in, and the per-app list to load.
Apple highlights recommendations at the top — turn on iCloud Photos, Offload Unused Apps, Auto Delete old Messages.
The list below is sorted by size — go after the big ones.
Empty Recently Deleted in Photos.

Photos app > Albums > Recently Deleted (at the bottom, may need Face ID/passcode).
Tap Select > Delete All.
Photos and videos stay in this folder for 30 days after you 'delete' them, holding their full storage — and many people don't realise.
This single step often frees several gigabytes.
Turn on iCloud Photos with Optimise.

Settings > Photos > iCloud Photos on, and Optimise iPhone Storage on.
The iPhone uploads photos to iCloud, then keeps small previews locally and downloads the full-size copies when you actually open them.
You need enough iCloud space — the free 5 GB rarely fits everything, but 50 GB iCloud+ is roughly £1 / $1 a month and worth it for the storage relief.
Offload big apps you don't use weekly.

Settings > General > iPhone Storage > tap a big app > Offload App.
The app icon stays on your Home Screen and your data is kept, but the app itself is removed.
Tap the icon to reinstall in seconds when you next want it.
Spotify, Netflix, Disney+, big games and old social apps are the usual candidates.
Clean WhatsApp / Messages media.

WhatsApp > Settings > Storage and Data > Manage Storage > Larger than 5 MB — review and delete bulk media you don't need.
Settings > Messages > turn on Keep Messages > 1 Year (down from Forever) to auto-clear old messages and their attachments after a year.
Years of group-chat memes really add up.
Clear Safari and Mail caches.

Settings > Safari > Clear History and Website Data.
Settings > Mail > Accounts > [your account] — for IMAP, the iPhone keeps a local cache; the cleanest fix is to remove and re-add the account, which clears the cache without losing any actual mail (it re-downloads from the server).
Don't do this on POP accounts — those keep the only copy on the phone.
Restart, then check again.

After clearing space, restart the iPhone.
The 'Used / Available' figure updates correctly after a reboot, and any background cleanup iOS does happens then.
If storage still says Almost Full after a real cleanup, look at the 'System' and 'Other' bar — large System or Other usually means you have a corrupted cache, and a backup + restore (or an iOS reinstall via Finder/iTunes) is the only thorough fix.

Frequently Asked Questions

Why does my iPhone Other/System storage keep growing?

Other / System storage on iPhone is a catch-all for caches, downloaded fonts, Siri voices, mail attachments, and bits of system data — and iOS doesn't expose granular controls for most of it.
The cleanest way to shrink Other is: turn on iCloud Photos with Optimise (so full-size photos move to iCloud), remove and re-add IMAP mail accounts (clears their cache), and clear Safari history and website data.
A full restart can free more.
If Other is still gigabytes after those steps, the only thorough fix is to back up, erase the iPhone, and restore from backup — which rebuilds the cache from scratch.
Most people don't need to go that far.